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a  practical  meatise 
Artificial 


Crown-.  Bridge-,  and  Porcelain-Work 


15  v 

GEOEGE    EVANS. 


FORMERLY    LECTURER    h.V    CROWN-    AND    BRIDGE-WuRK    IN    THE    BALTIMORE    COLLEGE    OF 

DENTAL    SURGERY;     MEMBER    OF    THE    NATIONAL    DENTAL    ASSOCIATION;    OF    THE 

DENTAL    SOCIETY    OF   THE    STATE   OF    NEW    YORK  :    OF    THE   FIRST    DISTRICT 

DENTAL    SOCIETY     OF    THE     STATE    OF    NEW     YORK;     OF    THE     NEW 

V'lUK     ODONTOLOGICAL     SOCIETY:     HONORARY     MEMBER     OF 

THE     MARYLAND     STATE    DENTAL    ASSOCIATION.    ETC. 


Seventh  Edition,  Revised  and  Enlarged. 


WITH    754    ILLUSTRATIONS. 


PHILADELPHIA  : 

THE  S.  s.  WHITE  DENTAL  MFG.   I  0. 

1905. 


vJ,<r-Y3^-|  * 


Copyright,  1888,  by  George  Evans. 

Copyright,  1889,  by  George  Evans. 

Copyright,  1893,  by  George  Evans. 

Copyright,  1893,  by  George  Evans. 

Copyright,  1896,  by  George  Evans. 

Copyright,  1900,  by  George  Evans. 

Copyright,  1905,  by  George  Evans. 


in 


r^ 


To 

William   Carr,  M.D.,  D.D.S., 

in  acknowledgment  of  his  professional  eminence 
and  his  services  for  dental  legislation  and  its  en- 
forcement in  the  State  of  New  York,  this  volume 
is  respectfully  inscribed  by 

THE  AUTHOR. 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 
Columbia  University  Libraries 


http://www.archive.org/details/practicaltreatisOOevan 


PREFACE  TO  THE  SEVENTH  EDITION. 


1  .\  this  seventh  edition  of  "Artificial  ( Irown-, Bridge-,  and  Porce- 
lain-Work" the  endeavor  has  been,  as  in  each  of  those  which  pre- 
ceded it,  to  better  meet  the  requirements  of  a  practical  treatise  for 
college  and  post-graduate  study  and  as  well  of  a  reference  book  for 
the  practitioner.  To  effect  this  in  the  present  state  of  the  art 
has  involved  a  revision  so  extensive  as  to  make  the  present  edition 
almost  a  new  work.  Like  all  books  of  its  kind  it  is  largely  a 
compilation  of  the  regularly  accepted  methods  of  practice. 
Recent  innovations  inserted  as  worthy  of  credit  and  recognition 
I  have  in  most  cases  practically  tested.  In  this  I  have  been 
guided  by  an  experience  of  nearly  forty  years  as  a  general  prac- 
titioner, the  last  twenty  of  which  have  been  specially  devoted 
to  Crown-  and  Bridge-Work,  supplemented  in  the  more  recent 
years  by  Porcelain-Work,  in  the  last  named  of  which  I  have  been 
assisted  by  a  previous  knowledge  of  the  properties  and  manipula- 
tion of  porcelain  bodies. 

The  discussion  of  pathological  conditions,  surgical  operations, 
and  of  therapeutic  indications,  metallurgy,  and  the  mechanical 
processes  involved  in  the  construction  of  appliances,  has  been 
limited  to  their  direct  relationship  to  the  work  in  hand.  Dental 
students  and,  still  more  so,  practitioners  are  supposed  to  be  gener- 
ally informed  respecting  them,  with  facilities  for  ready  reference 
to  works  specially  devoted  to  those  subjects. 

The  endeavor  in  this  treatise  has  always  been  to  make  the  text 
comprehensive  without  bulkiness,  concise  without  the   sacrifice 


VI 


PREFACE  TO  SEVENTH  EDITION. 


of  clearness  to  brevity  of  statement,  and  to  avoid  repetition  ex- 
cept where  it  conduced  to  better  understanding.  Methods  which 
permit  the  attainment  of  the  desired  results  without  the  devi- 
talization of  pulps,  and  with  the  least  mutilation  of  teeth,  and  the 
least  exposure  of  metal,  are  given  prominence.  So  also,  in  cases 
where  practicable,  constructions  are  advocated  which  permit  the 
work  to  be  removed  and  replaced  by  the  patient,  or  when  cemented 
to  place,  by  the  dentist. 

Acknowledgment  is  made  generally  throughout  the  text  to 
those  who  have  been  identified  with  or  prominent  in  advocating 
or  introducing  methods  of  procedure  which  are  novel  or  which 
tend  to  facilitate  the  performance  of  better  operations  in  a  prac- 
tical way. 

George  Evans. 

5.3  West  39th  St.,  New  York, 
June  17,  1905. 


CONTENTS. 


FART  I. 

PAGE 

PREPARATORY  TREATMENT  OF  TEETH  AND  ROOTS  FOR  CROWN- 
WORK    3 


CHAPTER  I. 

THE  PULPS  OF  TEETH.     Their  Preservation  or  Devitalization 
Disinfection  of  Dentin   and  Pulp-Capping 


CHAPTER  II. 

DEVITALIZATION  OF  THE  PULP.  Instantaneous  Devitalization 
— Cataphoresis — Excision  of  the  Crown  and  Instantaneous 
Extirpation  of  the  Pulp — Devitalization  with  Arsenic 11 

CHAPTER  III. 

PULPLESS  TEETH.  Requirements  of  Treatment — Preparation  of 
Root-Canals — Treatment  and  Disinfection — Closure  of  the 
Apical  Foramen  and  Filling  of  the  Canal — Use  of  Antiseptics.      15 


CHAPTER  IV. 

CHRONIC    ALVEOLAR    ABSCESS.     The    Usual    Forms— Alveolar- 

otomy — Amputation  of  the  Apex  of  a  Root 27 


CHAPTER  V 

SHAPING  TEETH  AND  ROOTS  FOR  CROWN-WORK.  Principles 
Involved — Preparation  of  Teeth  or  Roots  for  Collar  Crowns, 
and  Instruments  Used — For  Ready-Made  Porcelain  Crowns — 
Special  Preparation  of  Badly  Decayed  Teeth  or  Roots 34 


yjij  CONTENTS. 


PART  II. 
ARTIFICIAL  CROWN-WORK. 

CHAPTER  I. 

PAGE 

ARTIFICIAL  CROWN- WORK.  First  Authentic  Account  of  Artifi- 
cial Crown  or  Pivot  Teeth — The  First  Porcelain  Pivot  Teeth — 
Gold  Pivot-Teeth — First  Porcelain  and  Gold  Pivot-Tooth  or 
Crown — Richmond  Porcelain  and  Gold  Collar  Crown — The 
Earlier  Operations —-Morrison  and  Beers  Crowns — The  Foster 
and  Lawrence  Crowns — The  Mack  and  Howland-Perry  Crowns 
— The  Gates-Bonwill  Crown — The  How  Crown — The  Weston 
Crown — The  New  Richmond  Porcelain  Crown — Advantages  Con- 
ferred by  Improvements  in  Cements — Classification  of  Crown- 
Work    45 

CHAPTER  II. 

PRINCIPLES  INVOLVED  IN  CROWN-WORK.  Nomenclature  of 
Crown-Work — The  Object  of  Crowning  Operations — The  Sub- 
ject of  Occlusion — Malformed  Occlusal  Surfaces — The  Post 
in  Relation  to  the  Canals  and  Roots — The  Post  in  Re- 
lation to  Post  or  Dowel  Crowns — Short  and  Long  Crowns 
— Principles  Governing  the  Construction  of  Root-Caps  with- 
out Collars — Posts  in  Relation  to  Collar  Crowns — Selection 
of  Porcelain  Teeth — Dependence  of  Crown-Work  Operations  on 
Asepsis    52 

CHAPTER  III. 

THE  PORCELAIN  READY-MADE  CROWN  SYSTEM.  Method  of 
Preparation  of  the  Root — Screw-Posts — Use  of  Plaster  Model 
for  Fitting  Crowns — The  Logan  Crown — The  Fellowship  Crown 
and  the  Brewster  Crown — The  Davis  Crown — Ash's  Tube-Teeth 
and  Crowns   Gl 

CHAPTER  IV. 

PORCELAIN  CROWNS  WITH  VULCANITE  ATTACHMENT.  A  Tem- 
porary Crown    72 

CHAPTER  V. 

GOLD  COLLAR  CROWNS.  Construction  and  Adaptation  of  Col- 
lars—Methods of  Measurement — Fitting  of  Collars  to  Root 
or  Crown — Application  of  a  Local  Anesthetic — Collar  Crowns 
Hygienically    Considered    74 


C0XTENT8.  jx 

CHAPTER  VI. 

TAGH 

GOLD  COLLAR  CROWXS  WITH  PORCELAIN  FRONTS.  Incisors 
and  Cuspids:  Construction  and  Adaptation  of  the  Cap — The 
Post — .Method  of  Forming  Posts  to  Accurately  Fit  Canals — 
Post  and  Cap — Selection  and  Adaptation  of  Porcelain  Front — 
Protecting  the  Incisal  Edge — Backing  the  Porcelain  Front 
— Preparation  for  Investment — Soldering  and  Finishing  Bicus- 
pids and  Molars — Dr.  Stowell's  Method  of  Applying  a  Counter- 
sunk Tooth  or  a  Logan  Crown — Crowning  in  Cases  of  Abra- 
sion— Gold  Crowns  with  Porcelain  Fronts  for  Teeth  with  Liv- 
ing Pclps    83 

CHAPTER  VII. 

ALL-GOLD  COLLAR  CROWNS  FOR  BICUSPIDS  AND  MOLARS  CON- 
STRUCTED IN  SECTIONS.  Methods  of  Knuckling  the  Collar 
and  Giving  Contour — Forming  the  Occluding  Surface,  Methods 
Nos.  1,  2,  3,  4,  5,  G,  and  7 — All-Gold  Crowns  for  Incisors  and 
Cuspids — Cases  of  Abrasion  101 

CHAPTER  VIII. 

THE  GOLD  SEAMLESS  CAP-CROWN  SYSTEM.  Seamless  Root-Caps 
for  Crowns  with  Porcelain  Fronts — Incisors,  Cuspids,  and  Bi- 
cuspids— Impressions  and  Dies — Method  of  Stamping  Seamless 
Metal  Caps — All-Gold  Seamless  Bicuspids  and  Molars — Models, 
Dies,  and  Method  of  Swaging — All-Gold  Seamless  Incisors  and 
Cuspids    112 

CHAPTER  IX. 

IMPARTING  CONTOUR  TO  SEAMLESS  GOLD  CROWXS.  Crowns 
Swaged  on  Dies — Method  of  Slitting  and  Contracting  the  Neck 
— Use  of  Contouring  Pliers — External  Application  of  Metal — 
To  Contour  on  the  Die  with  a  Swager — Sectional  Mold  Method 
— Formation — Molds — Shaping  the  Cap — Ready-Made  Gold 
Crowns     1  IS 

CHAPTER  X. 

ADJUSTMENT  OF  SEAMLESS  GOLD  CROWNS.  Expansion  of  the 
Collar  and  Crown — Alteration  of  a  Side  or  Part  of  a  Crown 
— Alteration  of  the  Occluding  Surface — Contraction  of  the 
Neck — To  Deepen  the  Cusps — To  Point,  Lengthen,  or  Narrow 
in  Appearance  the  Labial  Cusp — To  Remove  the  Indentation 
Between  Cusps — Strengthening  and  Reinforcement  of  Seam- 
less Gold  Crowns — Method  of  Forming  a  Solid  Grinding-Sur- 
face — External  Reinforcement  of  Seamless  Gold  in  "Close 
Bites" — Comparative  Merits  of  the  Sectional  and  Seamless 
Methods  of  Constructing  Gold  Crowns 122 


x  CONTENTS. 

CHAPTER  XI. 

PAGE 

VARIOUS  FORMS  OF  GOLD  CROWNS  WITH  PORCELAIN  FRONTS. 
Porcelain  and  Gold  Crown  without  a  Collar — Roots  below 
Gum-Margin:  Special  Forms — Cup-Shaped  Cap:  Dr.  Van 
Woert's  Method — Dr.  Chupein's  Method — -Ready-Made  Post  and 
Disk — Dr.  Sanger's  Method — Double  Cap-Crown 129 

CHAPTER  XII. 

SETTING  ALL- PORCELAIN  CROWNS  ON  CAPPED  ROOTS.  The 
Logan:  Dr.  White's  Method— Collar- Cap — A  Simple  Method — 
The  Davis  Crown  on  a  Capped  Root 137 

CHAPTER  XIII. 

'TREATMENT  BY  CROWN-WORK  OF  FRACTURED  TEETH  AND 
ROOTS  AND  CASES  OF  IRREGULARITY.  Fractured  Crowns 
and  Roots — Longitudinal  Fracture — Slanting  Fracture  of  the 
Root — Restoration  by  Banding  and  Capping — Inlay  Method — 
Amalgam — Post  and  Amalgam — Perforation  of  a  Side- Wall  of 
a  Root-Canal  or  of  the  Dentin  at  the  Bifurcation  of  the  Roots 
— Dr.  Farrar's  Cantilever  Crown — Formation  of  the  Spur — 
Methods  of  Crowning  in  Cases  of  Irregularity 140 

CHAPTER  XIV. 

PARTIAL  CROWN-WORK.  Gold-Plate  Partial  Crowns— Gold  Hol- 
low or  Box  Inlays — Solid  Gold  Inlays  with  Extensive  Restora- 
tion of  Contour — Solid  Gold  Tips  for  Abraded  Pulpless  Front 
Teeth — Gold  Tips  in  Cases  of  Living  Pulps — Extensive  Resto- 
ration— Porcelain  and  Gold 149 

CHAPTER  XV. 

PROCESSES  CONNECTED  WITH  CROWN-  AND  BRIDGE-WORK. 
Correction  of  Excess  of  Solder — To  Securely  Attach  a  Crown 
— Importance  of  Removal  of  Flux  from  Interior  of  Crowns — 
Finishing  and  Polishing    160 

CHAPTER  XVI. 

CEMENTATION  OF  CROWN-  AND  BRIDGE-WORK.  Zinc  Oxyphos- 
phate — Method  of  Mixing — Application — Oxyphosphate  with 
Partial  Application  of  Gutta-Percha — Cementation  with 
Gutta-Percha — Dowel  Crowns — Collar  Crowns — Gutta-Percha 
Cement — Advantages — Method  of  Using — Method  of  Measuring 
the  Cement — To  Provide  for  Surplus  Cement — Requirements 
for  Success — Oxyphosphate  in  Combination  with  Gutta-Percha 
Cement — Amalgam    162 


coyTEyis.  xj 

PAET  III. 
BRIDGE-WORK. 

PAGE 

Introduction    177 

CHAPTER  I. 

CONSTRUCTION  OF  BRIDGE-WORK.  Mechanical  Principles- 
Preparation  of  the  Supporting  Teeth  of  Piers — Construction— 
Impressions  and  Models — Selection  and  Adjustment  of  the 
Artificial  Teeth — Backings — Self-Cleansing  Spaces — Invest- 
ment, Soldering,  and  Finishing — Warping,  How  to  Avoid — Con- 
struction in  Sections — Adjustment  and  Attachment — Con- 
struction of  Small  Pieces  of  Bridge- Work 181 

CHAPTER  II. 

SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK. 
Shoulders  on  the  Anterior  Crowns  or  Artificial  Teeth — Solid 
Porcelain  Dummies  with  Gold  Base — Diatoric  Tooth  Dummies 
— Solid  Gold  Dummies — A  Bar-Anchorage  Slot  in  a  Solid  Gold 
Crown — All-Gold  Hollow  Dummies — Connecting  Bands  or  Bars 
for  Bridges — Intervening  Roots — Shell  Crown  or  Anchorage — 
Seamless  Shell  Crown — Cementation  of  Shell  Crowns — Spe- 
cial Forms  of  Shell  Pin-Crowns — The  Carmichael  Crown — The 
Staple  Crown    201 

CHAPTER  III. 

EXTENSION  BRIDGES.  Principles  Governing— Construction- 
Spur  Support — A  Spur  Anchor 218 

CHAPTER  IV. 

BAR  BRIDGES.  Incisors  and  Cuspids — Anchoring  the  Bar — Bicus- 
pids and  Molars — An  Extension  Bar  Bridge — Gold  Inlay  An- 
chorage  Bar    224 

CHAPTER  V. 

PARTIAL  CAP-  AND  PIN-BRIDGE.  Construction— Limitations- 
Advantages  of  the  Method  in  Cases  with  Pulplf.ss  Teeth 229 

CHAPTER  VI. 

APPLICATION  OF  BRIDGE- WORK  IN  CASES  OF  PYORRHEA  AL- 
VEOLAR1S.  Dr.  Rhein's  Method  of  •'Splinting" — Partial  Cap- 
and  Pin-Bridge  Method — Use  of  Connecting  Collars 234 


xii  CONTENTS. 

CHAPTER  VII. 

PAGE 

REMOVABLE  AND  REPLACEABLE  PORCELAIN  FRONTS.  Pur- 
pose of  Their  Use — Modification*  of  Dr.  Wardwell's  Method — 
Dr.  Van  Woert's  Pliers  and  "Mason's  Detachable  Tooth" — A 
Simple  Form — Dr.  Alexander's  Method — Dr.  Bryant's  Method...  239 


CHAPTER  VIII. 

GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE-WORK.  Cen- 
tral or  Lateral  Incisors,  Cuspids,  or  Bicuspids — Centrals, 
Laterals,  or  Cuspids  Combined — Cuspids,  Bicuspids,  and  Molars 
Combined — Bicuspids  and  Molars  Combined:  Use  of  Partial 
Cap — Incisors,  Cuspids,  Bicuspids,  and  Molars  Combined 243 


CHAPTER  IN. 

REPAIR  OF  CROWN-  AND  BRIDGE-WORK.  The  Ordinary  Method— 
Dr.  Shriver's  Method — Dr.  W.  W.  Williamson's  Method — Dr. 
Starr's  Method — Dr.  E.  A.  Bryant's  Method — Advantages  of 
Detachable  Bridge-Work — Removal  of  Crowns  or  Bridges  Ce- 
mented with  Zinc  Phosphate — Removal  of  Crowns  or  Bridges 
Cemented  with  Gutta-Percha — Repair  of  a  Gold  Crown 262 


CHAPTER  X. 

THE  HYGIENIC  CONDITION  OF  THE  MOUTH  AS  AFFECTED  BY 
BRIDGE-WORK.  Consideration  of  the  Subject — Requirements 
— Methods  for  Cleanliness  and  Health 268 


CHAPTER  NI. 

REMOVABLE  AND  DETACHABLE  BRIDGE-WORK.  Limitations- 
Requirements — Removable  Incisor  or  Cuspid  Crown — Split  or 
Spring  Post — The  Tube — Union  of  Tube  and  Cap — Tapering 
Spring  Post — Crown-Post,  Detachable  or  Removable  Crown — 
Removable  Bicuspid  and  Molar  Attachments — Removable  Col- 
lar and  Partial  Cap — Flanged  Collar  Attachment — Spur  Col- 
lar Support — Removable  Clasp  and  Partial  Cap  Attachment: 
Cuspids:  Bicuspids — Connecting  Bars — for  the  Upper  Front 
Teeth — Construction  of  Removable  Bridge- Work 270 


CHAPTER  XII. 

REMOVABLE  PLATE  BRIDGE-WORK.  Form  of  Construction- 
Methods  of  Construction — Various  Styles — Dr.  Bonwill's 
Method — Dr.  Davenport's  Case  287 


CONTENTS.  x[[i 

CHAPTER  XIII. 

PAGE 

SPECIAL  FORMS  OF  DETACHABLE  AND  REMOVABLE  BRIDGE- 
WORK.  Sectional  Crown  Methods:  Dr.  Winder's — Dr.  Spen- 
cer's— Case  of  Dr.  Alexander's — Dr.  Litch's  Method — Dr.  Parr's 
Dovetail  Flange  Attachment — The  Griswold  System 304 

CHAPTER  XIV. 

THE  HOLLINGSWORTH  SYSTEM.  Construction  of  a  Gold  Crown 
(Bicuspid  or  Molar) — Solid  Gold  Cusps — Gold  Crowns  (Cen- 
trals, Laterals,  and  Cuspids) — Insertion  of  a  Porcelain  Fa- 
cing— Formation  of  the  Grinding-Surface  of  a  Bridge  in  One 
Continuous  Piece — Facing  for  All-Gold  Bridge 316 

CHAPTER  XV. 

CROWN-  AND  BRIDGE-WORK  COMBINED  WITH  OPERATIVE  DEN- 
TISTRY IN  DENTAL  PROSTHESIS.  Symmetry— Cases  Showing 
the  Results  of  Combined  Operations 325 

PART  IV. 

PORCELAIN    DENTAL  ART. 

Introduction    337 

CHAPTER  I. 

PORCELAIN  COMPOUNDS  OR  BODIES.  Ingredients:  Their  Chem- 
ical and  Physical  Character — Low-  and  High-Fusing  Porcelain 
Bodies — Coloring  of  Porcelain  Compounds — Gum  Enamel — 
Foundation  or  Basal  Body — Preparations  of  Porcelain  Bodies — 
Selection  of  the  Color  of  the  Porcelain  Body — Sample  Shades 
— Variation  in  Shade — Spatula  and  Brushes  Used — Prepara- 
tion of  Porcelain  Body  for  Use — Use  of  Gum  Tragacanth  or 
Starch — Application  of  Porcelain  Body   338 

CHAPTER  II. 

FURNACES.  Gas — Gasoline — Electric — Use  of  Furnaces — Advan- 
tages of  the  Electric  Furnace — Dental  Furnace  Pyrometer  ....   344 

CHAPTER  III. 

FUSING  OF  PORCELAIN.  Importance  of  the  Operation  of  Fusing 
— Shrinkage — Baking  or  Fusing — First  Bake — Second  Bare- 
Final  Bake — Cooling,  Annealing,  or  Tempering— Difficulty  At- 
tending the  Proper  Fusion  of  Small  Masses  of  Body — Method 
Used  to  Indicate  Point  of  Fusion — Advantages  of  tht:  Pyrome- 
ter in  Indicating  Fusion  Accurately  348 


xiv  CONTENTS. 

CHAPTER  IV. 

PAGE 

STAINING  OF  PORCELAIN.  Character  and  Purpose  of  Mineral 
Stains — Use  of  the  Colors — Application — Gradation  of  Shade 
— Fusing    353 

CHAPTER  V. 
CHARACTER    AND    SUITABILITY    OF    LOW-    AND    HIGH-FUSING 
PORCELAINS     FOR    INLAY-    AND    CROWN-WORK.     Require- 
ments— Comparative    Merits — Tests    of    Dental    Porcelains — 
Suitable  Application  of  Each  Grade 356 

CHAPTER  VI. 
PORCELAIN  INLAYS.  The  Earlier  Methods — Modern  Inlays  and 
Their  Merits — Instruments  and  Materials  Used  in  the  Adapta- 
tion of  Matrices — Preparation  of  Cavities — Formation  of  Gold 
Matrices  for  the  Low-Fusing  Porcelains — Platinum  Matrices 
■ — To  Facilitate  the  Shaping  of  a  Matrix — Molds  and  Dies  for 
— Oxyphosphate  Impressions — Process  of  Shaping  a  Matrix  by 
a  Mold  or  Die — Discussion  of  Proportion  of  Displacement  by  a 
Matrix — Removal  of  a  Matrix:  Gold — Platinum — Methods  to 
Aid  Removal — Investing  the  Matrix — Application  of  Porcelain 
Body — The  Jenkins  Low-Fusing  :  Application,  Fusing — Use  of 
Electric  Furnace  in  Baking  Low-Fusing  Porcelain — Estimated 
Degree  of  Heat — High-Fusing  Porcelain:  Application — First 
Bake — Second  Bake — Final  Bake — Comparative  Heat  of  the 
Final  Bake — Removal  of  a  Foil  Matrix — Preparation  for  Ce- 
mentation— Methods  of  Etching  with  Acid  or  a  Diamond — Use 
of  a  Lens — To  Aid  Adjustment  in  Cementation — Requirements  : 
Effect  on  Color — Operation  of  Cementation 358 

CHAPTER  VII. 

SPECIAL  OPERATIONS,  ROD  INLAYS,  AND  POINTS  TO  BEAR  IN 
MIND.  Large  Contour  Inlays — Use  of  Pieces  of  Porcelain 
Teeth — Use  of  Successive  Grades  of  Bodies — Subject  of  Occlu- 
sion— Porcelain  Inlays  in  Combination  with  Gold  or  Amalgam 
Fillings — Atrophy  and  •  Erosion — Porcelain  Tips — Porcelain 
Shoulders  Preferable  to  Pins  for  Retention — Wire  Loop. 

ROD  INLA\S.  Preparation  of  the  Cavity — The  Rod  Inlay — -Cemen- 
tation and  Finishing — Use  of  Porcelain  Teeth  to  Form  Rod 
Inlays. 

POINTS  TO  BEAR  IN  MIND.  To  Facilitate  Matrix  Adaptation  in 
Cervical  Cavities — To  Overcome  Contraction  of  Body — To  Aid 
Removal,  and  Remedy  Tear  of  Matrix — Advantages  of  the  Use 
of  a  Foundation  Body  in  Contour  Operations — Use  of  Lens — 
Porosity  of  Porcelain — Time-Saving  in  Inlay-Work — Edges  of 
Inlays- — Small  Inlays — Effect  of  Cement  on  Shade — Require- 
ments in  Inlay-Work — Conservative  Limitations  of  Inlay-Work.  377 


CONTENTS.  xv 

CHAPTER  VIII. 

PAGE 

PORCELAIN  AND  PLATINUM  CROWN-WORK.  Structural  Re- 
quirements— Platinum  Solder — Nature  of  Adhesion  of  Porce- 
lain Fused  on  Platinum — Application  of  Porcelain  Body  in 
Crown- Work — Baking — Degrees  of  Heat— Process  of  Construc- 
tion of  Collar  Crowns — Partial  Collar-Cap — Bicuspids  and 
Molars — Practical  Method  to  Form  Occluding  Section — Crown 
without  a  Collar:  Limitations — Jacket-Crown — Incisors  and 
Cuspids — Application  of  the  Porcelain  Veneer — Protection  of 
Incisal  Edge — -Porcelain  and  Platinum  Bicuspid  Cap-Crown 
with  Porcelain  Occluding  Surface — Porcelain  and  Platinum 
Crown  with  Metallic  Occluding  Surface — Porcelain  and  Plat- 
inum Tube-Crown — Application  to  Cases  of  Fractured  Crowns 
— Ready-Made  Crowns  on  Capped  Roots — Logan  Crown  on  Plat- 
inum Base  without  a  Collar— The  Davis  Crown  on  a  Capped 
Root — Veneering  of  Seamless  Gold  Crowns  with  Porcelain 
by  the  Aid  of  Low-Fusing  Porcelain  Body 387 

CHAPTER  IX. 

PORCELAIN  BRIDGE- WORK.  Character— Limitations— Structu- 
ral Requirements — Process  of  Construction — Cases  of  Porce- 
lain  Bridge- Work    403 


PART  V. 

MATERIALS  AXD  PROCESSES  USED  IN  CROWX- 
AXD  BRIDGE-WORK. 

CHAPTER  I. 

PLATES  AND  SOLDERS.  Platinum— Platinum  Foil  and  Wire- 
Platinum  and  Gold  Collar — Iridium — Gold — Gold  Alloys  fob 
Plate — Gold-Platinum  Lined  Plate — Platinized  Gold — Melting 
and  Refining  of  Gold  Scraps — Gold  Solders — Hard-Flowing 
Gold  Solder — Fluxed  Solder  Filings — Silver  Solder — Platinum 
Solder — Flux 411 

CHAPTER  II. 
PORCELAIN  TEETH.    Essentials— Fractures— Causes  of— Veneers.  417 


xvj  CONTENTS. 

CHAPTER  III. 

PAGE 

PROCESSES,  METHODS,  AND  MATERIALS.  Impression-Trays— 
Articulators  —  Impressions  —  Sectional  Impressions — Impres- 
sion-Compound and  Wax — Dental  Lac — Models — Articulating 
Impression  or  '"Bite"  and  Model — Metallic  Models  or  Dies — 
Fusible  Alloys — Moldine — How  to  Quickly  Make  a  Tube  and 
Fusible-Metal  Die — Counter-Die — Combination  Plaster  and 
Metal  Model — Cuttlefish  as  a  Molding  Material — Dental  Lac 
Intaglio  Dies — Wax  Cement 419 


CHAPTER  IV. 

MATERIALS  PRINCIPALLY  USED  FOR  INVESTMENTS.  Small 
Investments — Large  Investments — Method  of  Investing — Prep- 
aration of  Investment — Heating  the  Investment — Soldering- 
Blocks — Blowpipe  and  Method  of  Using  It — Preparation,  Appli- 
cation, and  Fusing  of  Solder — Solder-Pointer — Open-Flame 
Soldering — A  Union  by  Sweating — Soldering  by  Compound  Blow- 
pipe  Flame — Annealing    428 


CHAPTER  V. 

INSTRUMENTS,  APPLIANCES,  AND  MATERIAL   SPECIALLY  RE- 
QUIRED        437 


INTRODUCTION  TO  FIRST  EDITION. 


Of  the  origin  of  the  art  of  dentistry  no  one  can  speak  with 
certainty,  as  its  early  history  is  shrouded  in  the  mists  of  antiquity; 
but  dental  operations  are  recorded  in  very  remote  times. 

References  are  made  to  the  art  in  the  writings  of  Hippocrates, 
in  the  fifth  century  b.c.  Martial,  the  Latin  poet,  in  the  first 
century  b.c,  says  that  a  Roman  dentist  "Cascellius  is  in  the  habit 
of  fastening  as  well  as  extracting  the  teeth."  To  Lelius  he  says, 
"You  are  not  ashamed  to  purchase  teeth  and  hair;"  and  adds  that 
"the  toothless  month  of  Egle  was  repaired  with  bone  and  ivory;" 
also,  that  "Galla,  more  refined,  removed  her  artificial  teeth  during 
the  night." 

Horace,  in  the  same  century,  cites  the  case  of  the  "sorceresses 
Canidia  and  Sagana  running  through  the  city  and  losing  the  one 
her  false  hair,  the  other  her  false  teeth." 

Galen,  the  celebrated  physician,  in  the  second  century  a.d., 
also  speaks  of  the  art  of  dentistry  as  being  then  practiced. 

These  early  operations  were  limited  to  the  extraction  of  offend- 
ing teeth  and  the  replacement  of  those  which  had  been  lost  with 
substitutes  which  were  retained  in  position  by  means  of  narrow 
bands  or  ligatures  attaching  them  to  the  adjoining  natural  teeth, 
and  without  the  use  of  plates.  Crude  as  they  were,  they  formed 
the  first  expression  of  the  art  of  dentistry,  a  beneficent  art  from 
the  beginning,  in  that  it  sought  to  remedy  pathological  or  acciden- 
tal defects.     Confined  to  the  simplest  operations,  it  existed  for 


xviii  INTRODUCTION  TO  FIRST  EDITION. 

centuries,  and  then  was  apparently  lost  during  the  Dark  Ages,  to 
reappear  when  the  more  general  diffusion  of  knowledge  ushered 
in  the  modern  era  of  science  and  invention. 

After  its  revival,  dentistry,  so  much  of  it  as  was  known,  was 
in  a  measure  a  secret  art,  the  practice  of  which  even  within  the 
memory  of  men  now  living,  was  involved  in  mystery;  but  recent 
progress  has  lifted  the  veil,  and  dentistry,  in  the  treatment  of  the 
teeth  on  correct,  scientific,  rational  principles,  has  developed  an 
art  and  a  science  which  have  given  it  honorable  rank  among  the 
professions.  In  its  twofold  evolution  it  has  absorbed  from  every 
available  source  whatever  would  broaden  its  science  or  perfect  its 
art.  It  calls  to  its  aid  anatomy,  physiology,  pathology,  chemistry, 
therapeutics,  metallurgy,  sculpture,  and  mechanics,  with  each  of 
which  it  stands  in  closer  or  more  remote  relation;  and  the  prac- 
titioners of  dentistry  who  have  become  the  most  eminent  and  use- 
ful have  been  men  of  broad  attainments  and  great  versatility  of 
talent. 

In  the  history  of  all  progress,  movements  apparently  of  a  mure 
or  less  reactionary  character  are  recorded.  In  the  useful  arts 
especially  it  is  not  uncommon  to  find  a  return  to  forms  and 
methods  formerly  used,  but  long  since  discarded  and  forgotten. 
So  in  dentistry  we  find  methods  of  treatment  and  modes  of  practice 
once  in  vogue  but  long  fallen  into  disuse,  revived  with  improve- 
ments and  modifications  that  stamp  them  as  practically  redis- 
coveries. 

These  movements  are  not  to  be  regarded  as  retrogressive, 
because  the  modifications  which  accompany  the  reintroduction  of 
practical  ideas  and  inventions  attest  them  as  real  advances,  and 
indicate  clearly  that  the  cycle  of  knowledge  is  ever  widening  with 
experience.  This  volume  demonstrates  how  modern  dentistry 
has  utilized  the  principles  of  some  of  the  simplest  original  opera- 
tions, and  by  "proving  all  things,  holding  fast  that  which  is  good," 
has  attained  its  present  honorable  position  in  both  its  scientific  and 
artistic  departments. 


INTRODUCTION  TO  FIRST  EDITION.  XJX 

The  history  of  dentistry  of  later  years  is,  in  brief,  a  recital  of 
progress  and  improvement.  The  medical  profession  has  officially 
recognized  it  as  closely  allied  to  medicine  by  inviting  its  represen- 
tatives to  take  part  in  the  International  Medical  Congresses  on  the 
footing  of  professional  equality. 

Such  is  the  position  which  dentistry  has  attained.  Much  of 
the  progress  which  has  made  its  present  elevation  Dossible  must 
be  credited  to  the  dental  profession  of  the  United  States,  which 
has  been  justly  termed  the  cradle  of  modern  dentistry.  Here 
the  validity  of  the  idea  that  scientific  knowledge  should  form  the 
basis  of  training  for  practice  was  first  demonstrated  by  the  success- 
ful establishment  of  dental  schools;  here  the  first  journal  for  the 
interchange  among  dentists  of  thought  and  experience  was 
founded;  here  the  first  association  having  for  its  object  the  uplift- 
ing and  upholding  of  dentistry  by  the  mutual  helpfulness  of  its 
practitioners  had  its  origin;  here,  in  a  word,  dentistry  was  first 
divorced  from  mystery,  here  it  first  passed  the  narrow  confines  of 
a  mere  handicraft  and  earned  for  itself  the  right  to  be  classed 
among  the  learned  and  liberal  professions. 


ARTIFICIAL  CROWN-  AND  BRIDGE  WORK. 


Modern  artificial  crown-  and  bridge-work  belongs  to  the 
department  of  dentistry  formerly  termed  "mechanical;"  but  the 
judgment,  skill,  and  scientific  information  required  place  it  far 
above  ordinary  mechanical  dentistry,  which  has  sunk  to  a  low 
estate  since  the  introduction  of  vulcanite.  To  such  an  extent  has 
vulcanite,  by  reason  of  its  cheapness  and  ease  of  manipulation, 
superseded  other  materials  demanding  greater  knowledge  and 
skill  in  their  manipulation,  as  to  retard  the  higher  development 
of  prosthetic  dentistry,  and  indeed  to  divest  it,  in  the  hands  of 
those  who  depend  upon  vulcanite,  of  the  dignity  which  should 
belong  to  dentistry  as  a  profession. 

But  modern  crown-  and  bridge-work,  properly  understood  aud 
properly  performed,  takes  high  rank  in  dental  art,  and  offers  wide 
scope  for  versatility  of  talent  and  inventive  genius.  The  varied 
and  complicated  cases  presenting  for  treatment  frequently  suggest 
to  the  expert  novel  contrivances  and  methods  of  construction  and 
application.  Successful  practice  of  crown-  and  bridge-work 
depends  upon  a  thorough  mastery  of  the  underlying  principles, 
and  expertness  in  the  processes  involved,  governed  by  sound  judg- 
ment and  perfect  candor.  The  interests  of  the  patient  should  be 
paramount  to  every  other  consideration,  and  after  a  careful 
examination  he  should  be  given  an  accurate  statement  of  the 
applicability  of  the  system  to  his  case,  in  respect  to  usefulness, 
appearance,  durability,  and  comfort,  as  compared  with  other  pro- 
cesses and  appliances  in  use. 


xxjj  ARTIFICIAL  CROWN-  AXD  BRIDGE-WORK. 

Surgical  and  mechanical  operations  of  the  most  delicate  nature 
are  required.  Nothing,  indeed,  in  dentistry  demands  finer 
manipulation.  A  practical  consideration  of  the  subject  will  show 
that  a  knowledge  of  anatomy,  pathology,  and  therapeutics,  and 
as  well  mechanical  and  artistic  skill,  are  necessary  to  the  correct 
treatment  of  cases  and  the  proper  performance  of  the  operations 
indicated.  Among  the  principal  steps  in  an  operation  may  be 
named,  first,  the  preparatory  treatment  of  the  natural  roots  and 
teeth  for  the  final  process,  involving  the  diagnosis  of  present  or 
probable  lesions  and  the  prescription  of  whatever  remedial  or 
prophylactic  measures  may  be  needful;  second,  in  crown- work,  the 
adaptation  of  the  artificial  crowns  to  the  cervical  portion  of  the 
natural  roots  and  the  contiguous  membranes,  and  the  restoration 
of  the  articulation  and  the  anatomical  contour;  and,  in  bridge- 
work,  the  selection  of  suitable  teeth  or  roots  for  foundation  piers 
or  abutments,  and  the  choice  and  adaptation  in  constructive  prac- 
tice of  the  forms  which  will  insure  the  highest  degree  of  stability 
and  best  sustain  the  force  of  occlusion,  thereby  avoiding  abnormal 
positions  and  conditions. 

In  no  branch  of  dentistry  will  lack  of  knowledge  and  skill  or 
the  exhibition  of  carelessness  in  constructive  details  be  more 
plainly  evidenced  or  result  in  greater  proportion  of  injury  instead 
of  benefit.  Many  failures  are  to  be  attributed  to  attempts  to  per- 
form bridge-work  operations  with  about  the  same  expenditure  of 
time  on  the  part  of  the  dentist  and  of  money  on  the  part  of  the 
patient  as  in  plate-work.  There  is  no  such  relationship  between 
these  two  methods  of  procedure. 

The  practice  of  crown-  and  bridge-work  by  dentists  possessing 
the  requisite  attainments  and  governed  by  correct  ethical  princi- 
ples gives  results  which  have  gradually  established  its  value,  re- 
moving erroneous  impressions  and  insuring  a  wide  professional 
and  public  indorsement  of  this  important  branch  of  prosthetic 
dentistry.  Its  extraordinary  facilities  for  preserving  and  replac- 
ing teeth  have  made  for  it  a  high  position  in  dental  art. 


PART  I. 


PREPARATORY  TREATMENT  OF  TEETH  AND 
ROOTS  FOR  CROWN-WORK. 


PREPARATORY  TREATMENT  OF  TEETH  AND  ROOTS 
FOR  CROWN-WORK. 


GENERAL  CONSIDERATIONS. 


Preparatory  treatment  of  teeth  and  roots  for  crown-work 
includes,  in  addition  to  the  shaping  required  to  fit  them  for  the 
reception  of  the  crowns,  the  bringing  about  of  the  healthiest 
possible  condition  in  the  teeth  and  roots  and  the  adjacent  parts, 
as  the  cure  of  existing  lesions,  the  removal  of  calculus  where 
necessary,  and  the  adoption  of  such  measures  as  shall  prevent  the 
recurrence  of  old  troubles  or  the  inception  of  new. 

Notwithstanding  all  that  advanced  knowledge  of  therapeutic 
agents  and  skill  in  their  use  permit,  there  are  many  teeth  and 
roots  which  cannot  be  rendered  suitable  for  the  successful  applica- 
tion of  crown-  or  bridge-work.  Roots  which  are  permeated  and 
softened  by  decay,  exposed  or  loosened  from  absorption  of  the 
gums  and  alveoli,  or  affected  with  irremediable  disease  of  the 
investing  membranes,  should  be  thus  classed.  Cases  in  which 
abscess  with  necrosis  has  extensively  impaired  the  walls  of  the 
alveoli  are  equally  intractable. 

Experience  shows  that  the  results  in  this  department  of  den- 
tistry depend  largely  upon  diathesis  or  constitutional  tendency 
and  upon  the  attention  given  to  the  preservation  of  the  health 
of  the  mouth;  and  these  conditions  should  be  carefully  estimated 
in  the  selection  of  a  system  of  treatment  and  the  method  of  its 
application. 


PART  I. 
CHAPTER    I. 

The  Pulps  of  Teeth. 

their  preservation  or  devitalization— disinfection  of  dentin 
and  pulp-capping. 

The  preservation  of  the  vitality  of  the  pulps  of  the  teeth  is  as 
essential  in  crown-  and  bridge-work  as  in  any  other  operation. 

The  excision  of  natural  crowns  for  the  purpose  of  utilizing  their 
roots  as  abutments  for  bridge-work  is  extensively  practiced,  and  is 
defended  on  the  theory  that  the  vitality  of  the  dentin  is  to  an  ex- 
tent maintained  by  the  cementum  after  the  extirpation  of  the  pulp, 
or  that  the  pulp,  being  the  formative  organ,  is  of  no  further  value 
in  a  fully  developed  tooth  when  root-canal  treatment  is  properly 
conducted.  That  this  practice  is  fallacious  and  to  be  followed  only 
in  exceptional  cases  is  readily  made  evident. 

The  pulp  after  going  through  the  progressive  changes  which 
constitute  its  original  function  assumes  a  fixed  anatomical  char- 
acter as  the  source  of  the  vascular  and  nervous  supply  from  which 
the  dentin  derives  and  maintains  its  vitality.  The  protoplasmic 
bodies  of  the  pulp  unite  with  the  living  matter  of  the  tubuli,  which 
anastomose  to  a  limited  extent  with  those  of  the  cementum  through 
the  intervening  protoplasmic  bodies  in  the  interzonal  layer. 

This  distribution  and  relative  connection  of  living  matter  refers 
to  an  existing  state  of  perfect  vitality  of  all  the  parts.  When  the 
pulp  loses  its  vitality,  an  entirely  different  condition  results.  The 
tubuli  are  then  deprived  of  vital  circulation,  except  along  the  line 
of  the  outer  portion  of  the  dentin,  where,  in  the  interzonal  layer, 
the  fibrilla3  anastomose  with  the  living  matter  of  the  cementum. 
The  vitality  supported  by  this  anastomosis  is  almost  entirely  con- 
fined to  this  part,  the  nutrient  supply  being  insufficient  to  take 
over  the  functions  of  the  pulp  and  maintain  circulation  in  the 
main  body  of  the  dentin.    (See  Plates  T,  II,  III.) 

5 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


1  Plate  I. — Longitudinal  section  of  the  root  of  a  superior  bicuspid,  at 
junction  of  dentin  with  cementum.  C,  cementum;  D,  dentin;  I,  interzonal 
layer;  L,  lacunae  of  cementum.     X  175. 


Plate  II. — A  field  taken  from  Plate  I  in  position  marked  A.     L,  lacunae  of 
cementum;  C,  canaliculi  of  dentin;  I,  interzonal  layer.     X  210. 


Plate  III. — A  field  taken  from  Plate  I  in  position  marked  B.  L,  L,  L, 
lacunae  of  cementum;  I,  interzonal  layer;  D,  dentinal  tubes  and  their  nearest 
approach  to  the  lacunse.     X  210. 

A  study  of  these  plates  demonstrates  the  limited  nature  of  the  anastomosis 
of  the  fibers  of  living  matter  of  the  dentin  and  cementum. 


Plate  I. 


Plate  II. 


Plate  III. 


From  Specimens  Made  by  M.  H.  Fletcher,  M.  D.,  Dentist.     Cincinnati*.  Ohio. 


E.     MOEBIUS.     CAMDEh 


THE  PULPS  OF  TEETH.  7 

Chemical  analysis  of  the  dentin  shows  that  the  organic  matter, 
consisting  principally  of  the  fibrillse,  exists  in  the  proportion  of 
nearly  25  per  cent,  to  64  per  cent,  of  lime-salts.1 

When  the  pulp  has  been  removed,  the  devitalized  fibrillse  still 
remain,  and,  unless  antiseptic  root-canal  treatment  is  thoroughly 
carried  out,  their  disintegration  generates  septic  gases  capable  of 
producing  irritation  of  the  cementum  and  pericementum.  An 
examination  of  the  investing  membranes  of  pulpless  teeth  as 
treated  usually  shows  the  existence  of  a  percentage  of  abnormal 
conditions,  by  which  their  firmness  is  to  an  extent  impaired,  their 
susceptibility  to  acute  inflammation  increased,  and  their  reli- 
ability as  foundations  for  crown-  or  bridge-work  greatly  lessened 
as  compared  with  teeth  which  have  living  pulps.  Frequently  such 
conditions,  when  found  in  evidence  in  connection  with  the  work  of 
some  of  our  best  operators,  are  attributable  more  to  the  difficulties 
which  interfered  with  the  perfect  performance  of  root  treatment 
than  carelessness  or  lack  of  skill.  Observation  also  has  shown  the 
author  that  the  dentin  of  gold-capped  pulpless  natural  teeth  in  the 
course  of  years  gradually  softens  sufficiently  to  impair  their 
strength. 

Cap-crown  work  frequently  furthers  the  preservation  of  pulps  in 
the  posterior  teeth.  Thus,  in  a  case  verging  on  exposure,  only 
partial  removal  of  the  decay  is  often  necessary,  as,  when  the  opera- 
tion is  completed,  the  natural  crown  will  be  hermetically  inclosed 
by  the  artificial  one.  In  bridge-work,  proper  methods  of  practice 
will  also,  in  a  large  percentage  of  cases,  permit  the  anterior  teeth 
to  be  used  as  abutments  without  the  extirpation  of  their  pulps  or 
the  excision  of  their  crowns. 

Preparatory    Processes. 

That  extirpation  of  the  pulp  and  excision  of  the  natural  crown  or 
crowns,  especially  of  incisors  or  cuspids,  will  at  times  simplify  the 
work  and  permit  better  forms  of  construction  is  undeniable.     Be- 

1  The  analysis  of  dentin  by  Dr.  G.  V.  Black  gives  an  average  of — 

Lime-salts    63.54 

Organic  matter    25.36 

Water    11-06 

Age  slightly  lessens  the  proportion  of  living  matter  and  increases  the  per- 
centage of  lime-salts. 


8  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

sides,  the  question  of  root-canal  treatment  is  not  to  be  as  seriously 
considered  in  relation  to  front  as  to  back  teeth,  where  its  perfect 
performance  is  not  so  easy  of  accomplishment.  A  few  operators 
contend  that  the  removal  of  the  entire  enamel  and  a  portion  of  the 
dentin  of  a  bicuspid  or  molar  tooth  is  usually  necessary  to  properly 
shape  it  for  a  collar  or  cap-crown;  that  consequently  the  removal 
of  the  pulp  is  demanded  and  should  precede  the  operation.  This 
is  undoubtedly  true  if  a  tooth  is  to  be  divested  or  ''barked"  of 
its  enamel  in  the  manner  mentioned;  but  such  extreme  methods 
in  the  preparation  of  teeth  for  crowns  are  not  generally  accepted 
as  necessary,  especially  if  the  teeth  are  sound  and  are  to  be  used  as 
piers  to  support  bridge-work. 

Extirpation  is  demanded  only  for  those  pulps  whose  permanent 
preservation  cannot  be  placed  beyond  doubt,  as  failure  involves 
more  serious  consequences  in  crown-  and  bridge-work  than  in 
filling  operations. 

The  lesions  of  the  pulp  which  seem  to  require  its  extirpation, 
according  to  generally  expressed  opinion,  are  exposure  with  hyper- 
trophy or  rupture  of  the  pulp-sac,  congestion,  and  pulpitis  which 
does  not  yield  promptly  to  remedial  treatment.  Pulps  actually 
exposed  by  decay  are  seldom  found  in  a  normal  condition  other- 
wise, and  they  are  only  rarely  proper  or  hopeful  subjects  for 
remedial  treatment.  Atrophy  of  the  membrana  eboris,  or  invest- 
ing membrane,  which  comprises  the  layer  of  odontoblasts,  usually 
exists  at  the  part  exposed,  and,  as  any  subsequent  calcification 
must  depend  on  the  activity  of  the  odontoblasts,  it  is  evident  that 
the  existence  of  the  condition  referred  to  affords  a  strong  argument 
against  the  advisability  of  capping  pulps  with  extensive  or  even 
slight  exposure.  The  difficulty  of  securing  a  condition  of  asepsis 
of  the  exposed  and  diseased  parts  so  perfect  as  to  assure  them 
against  the  invasion  of  micro-organisms  subsequent  to  capping  is 
an  additional  argument  against  the  operation. 

Pulps  which  are  in  a  normal  condition,  still  protected  by  a 
layer  of  even  decomposed  or  partly  decomposed  dentin,  usually 
admit  of  successful  treatment.  In  such  cases  the  decayed  dentin 
may  be  excavated  from  the  side-walls  of  the  cavity,  but  that  in 
the  region  of  the  pulp  should  be  only  superficially  removed;  in 
some  cases  this  portion  may  be  allowed  to  remain  undisturbed. 

Disinfection  of  Dentin  and  Pulp=Capping. — The  capping  of  a 
pulp  should  include,  as  a  necessary  precaution  against  subsequent 


THE  PULPS  OF  TEETH.  9 

irritation,  the  thorough  disinfection  of  any  remaining  decomposed 
dentin.  An  excellent  method  of  disinfection  is  to  first  thoroughly 
wash  the  cavity  several  times  with  tepid  water  thrown  gently  from 
the  large  point  of  a  syringe  around  the  sides  of  the  cavity;  then, 
taking  measures  to  prevent  the  entrance  of  saliva,  wipe  the  cavity 
with  absorbent  cotton  and  pass  over  its  surface  a  light  current  of  hot 
air  from  a  hot-air  syringe.  The  heat  should  be  sufficient  to  cause 
some  discomfort  to  the  patient,  but  not  enough  to  produce  irrita- 
tion of  the  pulp.  The  dried  cavity  is  then  immediately  saturated 
with  carbolic  acid  previously  warmed1  to  the  normal  temperature 
of  the  body  by  holding  the  pellet  of  cotton  on  which  it  is  applied 
over  the  flame  of  a  lamp  for  a  moment.  The  carbolic  acid  relieves 
any  pain  caused  by  the  evaporation  of  moisture,  and  disinfects 
and  sterilizes  any  decomposed  matter  in  proximity  to  the  pulp. 
The  object  of  the  application  of  the  carbolic  acid  having  been 
accomplished,  the  surplus  may  then  be  removed  from  the  surface. 
To  this  end  the  cavity  should  first  be  wiped  with  absorbent 
cotton,  and  hot  air  again  introduced  to  evaporate  the  carbolic  acid 
sufficiently  to  give  a  dry  appearance  to  the  surface.  This  second 
application  of  hot  air,  owing  to  the  effect  of  the  drug,  will  cause 
little  or  no  pain. 

This  method,  if  practiced  early  in  the  preparation  of  the  cavity, 
will  be  found  to  considerably  obtund  sensation,  and,  through  the 
dryness  secured,  to  materially  facilitate  the  removal  of  the  decom- 
posed dentin.  A  reasonable  amount  of  the  decayed  portion 
should  be  cut  away,  as  it  lessens  the  difficulty  of  proper  disinfec- 
tion. For  excavating  in  the  region  of  the  pulp-chamber,  spoon- 
shaped  excavators  should  be  used  invariably.  For  the  thorough 
disinfection  of  dentin  and  removal  of  hypersensitive  conditions, 
the  author  practices  the  method  of  previously  placing  and  sealing 
in  the  cavity  for  from  two  days  to  a  week  a  mixture  of  precipitated 
chalk  and  carbolic  acid  and  oil  of  cloves  in  equal  parts.  A  small 
quantity  of  aristol  may  also  be  added.2 

The  disinfected  dentin  over  the  pulp  is  then  varnished  with 

1  Thermal  shock  to  the  pulp  is  as  unwarranted  from  the  application  of  cold 
carbolic  acid  as  if  produced  in  any  other  manner. 

2  The  chalk  is  placed  in  a  mortar,  and  the  carbolic  acid  and  oil  of  cloves 
gradually  introduced  and  thoroughly  incorporated  with  the  chalk  by  tritura- 
tion until  the  mixture  becomes  a   plastic  mass. 


10  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

chloro-gutta-percha,  or  some  other  preparation  suitable  for  the 
purpose,  and  capped  with  oxyphosphate  or  oxychlorid,  as  pre- 
ferred. When  the  capping  is  set,  the  remainder  of  the  cavity  is 
filled  with  the  same  cement  as  the  capping,  or  with  amalgam. 

Some  preference  is  given  to  zinc  oxychlorid  as  a  pulp-cap- 
ping over  the  oxyphosphate,  because  of  its  antiseptic  properties; 
but  its  use  invariably  requires  a  thorough  application  of  chloro- 
gutta-percha  to  thin  areas  of  dentin  over  the  pulp. 

Pulp-capping,  when  necessary,  should  precede  any  other  opera- 
tion, and  no  subsequent  procedure  is  admissible  until  the  success 
of  that  operation  is  assured,  the  time  allowed  for  this  purpose 
being  governed  by  the  requirements  of  each  case.  A  non-vital 
condition  of  the  pulp  in  one  root  of  a  tooth  contraindicates  any 
attempt  to  preserve  it  in  any  of  the  other  roots,  in  connection  with 
crown-  and  bridge-work. 

The  rubber-dam,  when  its  use  is  practicable,  will  be  found  a 
material  aid  in  pulp-capping  operations. 


CHAP  TEE    II. 

Devitalization  of  the  Pulp. 

instantaneous  devitalization — cataphoresis — excision  of  the 
crown  and  instantaneous  extirpation  of  the  pulp— devi- 
talization with  arsenic. 

When  devitalization  of  a  pulp  is  necessary  in  preparation  for 
crown-work  two  methods  are  practiced  :  the  heroic, — instantaneous 
devitalization,  or  extirpation, — and  gradual  devitalization,  by 
arsenical  treatment. 

Instantaneous  Devitalization. — This  can  be  accomplished  by 
first  administering  to  the#  patient  sufficient  nitrous  oxid  to  produce 
partial  anesthesia,  then  with  a  drill  quickly  opening  into  the  pulp- 
chamber,  and  lacerating  the  pulp  well  up  the  canal  with  a  probe 
or  smooth  broach.  Instantly  afterward  a  pellet  of  cotton,  satu- 
rated with  carbolic  acid,  should  be  forced  up  the  canal,  and,  if 
possible,  left  until  the  next  day,  when  the  pulp  will  be  found  in 
a  coagulated  mass  that  is  easily  removed  entire. 

Devitalization  of  the  pulp  as  just  described  is  practicable  only 
in  teeth  in  normal  condition.  In  acute  inflammation,  after  lacera- 
tion of  the  pulp,  warm  water  should  be  gently  injected  into  the 
pulp-chamber,  and  sedative  agents  then  applied.  The  devitaliza- 
tion of  the  pulp  should  subsequently  be  completed  by  whatever 
method  is  preferred  and  the  pulp  extirpated. 

Cataphoresis. — In  cases  of  actual  exposure  the  rubber-dam 
can  be  applied,  the  exposed  pulp  obtunded  with 
hydrochlorate  of  cocain,  applied  in  saturated 
solution;  the  diffusion  may  be  hastened  by  elec- 
trolysis. As  soon  as  the  action  of  the  cocain  is 
manifest,  the  pulp  may  be  extirpated. 

Excision  of  the  Crown  and  Instantaneous 
Extirpation  of  the  Pulp  is  practiced  as  follows : 
Two  parallel  grooves  are  cut  opposite  to  each 
other,  through  the  enamel,  deep  into  the  dentin, 
one  on  the  labial  portion  of  the  tooth  and  the 
3  11 


12 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


other  on  the  palatal  or  lingual  wall,  close  to  the  gum,  with  a 
rapidly  revolving  corundum  or  vulcarbo  disk  (Fig.  1).  Then  with 
excising  forceps,  the  cutting-edges  of  which  are  inserted  in  these 
grooves,  the  crown  is  quickly  severed  from  the  root  (Fig.  2).  The 
pulp  either  adheres  to  the  excised  crown,  leaving  the  canal  empty, 
or  remains  in  the  root,  fully  exposed.  In  the  latter  case,  a  pointed 
piece  of  orange-wood,  previously  cut  to  fit  the  canal,  and  saturated 
with  carbolic  acid,  is  driven  with  a  quick  blow  into  the  pulp 
toward  the  apex  of  the  root  (Fig.  3).  When  the  wood  is  with- 
drawn, the  pulp  usually  adheres  to  it;  if  not  the  wood  is  instantly 
Fig.  2.  reinserted,  cut  off,  and  drilled  out  with  the 

pulp,  using  Gates-Glidden  drills  in  the  upper 
portion  of  the  canal. 

Expertly  performed,  this  operation  is  ad- 
vantageous, though  it  should  be  confined  to 
teeth  the  pulps  of  which  are  in  normal  condi- 
tion.  Practical  experience  shows  fig.  3. 
that  in  such  cases  it  is  attended 
with  the  most  satisfactory  gen- 
eral and  final  results. 

Only  trifling  pain  is  felt  by 
the  patient,  as  the  pulp  is 
paralyzed  by  shock  in  the  ex- 
cision of  the  crown,  or  by  being 
forced  upward  toward  the  fora- 
men and  against  the  walls  of  the  canal.  The  subsequent  vitality 
of  the  cementum  is  assured  by  the  instantaneous  procedure,  and 
discoloration  of  dentin  and  enamel  to  a  noticeable  extent  seldom 
occurs  when  the  natural  crown  is  utilized  in  bridge  operations. 

The  objections  to  the  procedure  are,  that  if  the  pulp  is  not 
successfully  extracted  entire  with  the  wood  the  canal  becomes 
filled  with  clotted  blood,  which  is  difficult  to  remove  from  the 
extreme  end;  also  that  the  root  and  socket  are  jarred  by  the 
forceps  in  excising  the  crown. 

In  cases  of  actual  exposure  in  which  excision  of  the  crown 
cannot  be  safely  practiced — as,  for  instance,  in  a  bicuspid — a  por- 
tion of  the  walls  and  grinding-surface  may  be  removed  to  the  line 
of  the  root-canal,  the  pulp  obtunded  with  carbolic  acid,  and  the 
wood  point  then  forced  up  the  root-canal  in  the  same  manner  as 
when  the  crown  is  excised 


DEVITALIZATION  OF  THE  PULP.  13 

Devitalization  with  Arsenous  Acid — The  methods  of  devital- 
izing previously  described  are  applicable  principally  to  the  pulps 
of  incisors  and  cuspids.  In  the  posterior  teeth,  which  do  not  so 
well  permit  the  heroic  treatment,  recourse  is  had  to  arsenous  acid, 
notwithstanding  the  numerous  objections  to  its  use.  Two  theories 
as  to  the  mode  of  its  action  in  devitalizing  are  widely  entertained : 
First,  that  its  toxic  effects  produce  hyperemia,  which  stops  circu- 
lation; the  other  is  thrombosis.1 

This  theory  of  thrombosis  might  account  for  the  gradual  devi- 
talization of  the  pulp  toward  the  foramen. 

Whatever  the  action  of  arsenic  on  the  pulp  may  be,  it  always 
causes  an  infiltration  of  the  tubuli  of  the  dentin  with  certain 
constituents  of  the  blood,  probably  the  liquor  sanguinis.  To  an 
extent  the  residue  of  the  infiltration,  after  the  devitalization  of 
the  pulp,  remains  in  the  tubuli,  increasing  the  difficulty  of  pro- 
ducing an  aseptic  condition  of  the  dentin.  It  is  asserted  that 
arsenic  sometimes  affects  the  vitality  of  the  cementmn. 

Arsenic,  when  used,  should  be  applied  directly  to  the  pulp  in 
the  smallest  quantity  possible  to  effect  its  devitalization,  and 
securely  sealed  in  the  cavity. 

In  cases  of  non-exposure  requiring  its  application,  a  small 
opening  into  the  pulp-chamber  should  be  made.  This  can  be 
accomplished  with  but  little  pain  to  the  patient  with  a  very  small, 
sharp,  spear-headed  drill,  rapidly  revolved  by  the  engine.  The 
drill  should  be  held  steadily  under  gentle  pressure  at  one  point  in 
the  line  of  the  intended  exposure,  until  the  pulp  is  slowly  and 
gradually  reached,  and  not  suddenly  punctured  with  the  drill- 
point.  The  drill  should  be  occasionally  removed  and  the  cavity 
flooded  with  carbolic  acid  during  the  operation.  Cataphoresis 
may  also  be  practiced. 

Arsenic,  combined  with  agents  which  are  non-coagulants  of 
albumin,  may  be  used  in  preference  to  the  same  drug  combined 
with  creasote  or  carbolic  acid.  Dr.  Harlan's  method  is  to  apply 
an  anodyne,  such  as  wine  of  opium,  for  a  minute  or  two,  and  then 
the  following  paste : 

R — Arsenous  acid,  5i ; 

Muriate  of  cocain,  5ij ; 
Lanolin  in  quantity  sufficient  to  make  a  stiff  paste. 

1  See  Dr.  L.  C.  IngersolFs  "Dental  Science,  Questions  and  Answers,"  page  96. 


14  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 

The  application  should  be  kept  in  position  no  longer  than  is 
necessary  to  effect  the  devitalization  of  the  pulp,  twelve  to  forty- 
eight  hours  being  sufficient.  The  pulp  is  then  punctured,  a 
saturated  solution  of  tannin  in  glycerin  applied  and  securely 
sealed  in  the  cavity,  and  the  patient  dismissed  for  several  days, 
when,  in  favorable  cases,  the  pulp  can  be  removed  entire.  The 
saliva  should  be  entirely  excluded,  the  rubber-dam  being  applied 
when  practicable,  and  hydrogen  peroxid  or  absolute  alcohol,  in- 
stead of  water,  used  in  the  treatment. 

When  creasote  or  carbolic  acid  is  used  in  combination  with 
arsenic,  the  same  method  of  subsequent  treatment  may  be  prac- 
ticed. 

When  the  position  of  the  tooth  or  root  makes  the  application  of 
the  rubber-dam  extremely  difficult  or  impracticable,  the  operation 
can  be  successfully  conducted  without  its  aid  in  this  way :  At 
short  intervals  during  operative  procedures,  at  each  sitting  of  the 
patient,  thoroughly  syringe  the  pulp-cavity  with  hydrogen  peroxid, 
preventing  the  entrance  of  the  saliva  by  at  once  inserting  a  pellet 
of  cotton  saturated  with  the  peroxid,  oil  of  cloves,  or  some  other 
antiseptic.  The  tooth  can  then  be"  protected  from  the  saliva  by 
any  of  the  usual  methods  practiced,  and  the  treatment  proceeded 
with. 


CHAPTER    III. 

Pulpless  Teeth. 

requirements  of  treatment— preparation  of  root-canals— 
treatment  and  disinfection— closure  of  the  apical  fora- 
men and  filling  of  the  canal— use  of  antiseptics. 

Requirements  of  Treatment — The  treatment  of  pulpless 
teeth  or  roots  consists  in  as  thorough  performance  as  possible  of 
the  following  operations : 

First.     Enlargement  of  the  canal  and  removal  of  the  contents. 

Second.  Disinfection  of  the  root-canal  and  the  dentin,  and 
the  establishment  of  permanent  aseptic  conditions  by  mummifica- 
tion of  the  contents  of  the  tubuli. 

Third.  Closure  of  the  apical  foramen  and  prevention  of 
future  infection  from  the  oral  cavity  by  hermetical  closure  of  the 
entrance  to  the  canal. 

Preparation  of  Root=CanaIs — A  knowledge  of  the  usual  posi- 
tions of  the  root-canals  in  the  different  teeth  is  essential  for  a 
generally  successful  performance  of  this  operation,  which  is 
greatly  facilitated  by  the  ease  with  which  direct  access  to  the 
root-canals  is  obtained  in  crown-work. 

In  all  cases  in  the  preliminary  removal  of  tooth-structure  suffi- 
cient of  the  crown  should  be  left  to  easily  permit  application  of 
rubber-dam  and  the  retention  of  dressings  with  gutta-percha  seals. 
When  teeth  are  broken  down  or  extensively  decayed  below  the 
gum-margin  and  hypertrophied  gum-tissue  invades  the  cavity, 
the  diseased  tissue  should  be  first  cut  out,  the  cervical  section  of 
the  margin  of  the  cavity  trimmed,  and  an  antiseptic  dressing 
applied.  The  cavity  should  then  be  packed  with  gutta-percha 
well  anchored  either  against  the  adjoining  tooth  or  in  the  orifice 
of  the  pulp-cavity,  in  such  way  as  to  stop  the  hemorrhage  and 
press  back  the  tissue  by  the  time  for  the  next  treatment.  In 
the  preliminary  treatment  of  a  pulpless  tooth  a  probe  can  be 
inserted  in  the  root-canal,  to  be  withdrawn  when  the  packing 
is  completed,  leaving  a  vent  for  the  escape  of  gases  in  such  cases 

15 


16 


CROWX-,  BRIDGE-,  AXD  PORCELAIX -WORK. 


Fig.  4. 


Fig. 


as  suggest  it.  In  the  anterior  teeth,  the  removal  of  the  coronal 
section  directly  exposes  the  pulp-chamber.  In  bicuspids  and 
molars,  for  all-gold  crowns,  the  leveling  of  the  occluding  surface 
(see  Fig.  4)  and  removal  of  a  portion  of  the  side  most  involved  by 
decay  should  be  preliminary.  A  sufficient  opening  is  first  made 
into  the  center  of  the  pulp-chamber  in  a  line  with  the  root-canals 
to  give  free  and  direct  access  to  them,  and  any  remaining  portion 
of  the  pulp  is  removed  with  broaches.     A  few  fibers  of  cotton 

twisted  around  the  serrated  portions  of  the  broach 

will  admit  of  its  easy  removal  in  case  of  breakage. 

The  canals  are  then,  guided  by 

frequent    explorations   with    a 

fine  probe,  carefully  enlarged 

with  Gates-Glidden  drills  (Fig. 

5).  At  least  three  sizes — large, 

medium,  and  small — of  drills 

each   for  the   right-angle   and 
side,  a,  the  line  to    the   direct   hand-piece   are   re- 

wbich    the    crown  ,  x 

quired.      Very    little,    if   any, 

pressure   should   be  put  upon 

them  when  in  motion.  Under 
pressure  in  a  curved  root  a  small  drill  might  be  broken  off  or 
forced  through  the  apical  foramen  with  disastrous  consequences, 
where  alveolar  abscess  did  not  exist.  Neither  should  drills  be 
forced  into  canals  closed  by  calcification,  nor  beyond  the  line  of 
the  zone  of  cementum  at  the  end  of  the  root,  nor  through  a  con- 
striction which  a  fine,  flexible  probe  cannot  enter,  nor  around  a 
curve  sharp  enough  to  be  unsafe  to  pass.  A  slight  pain  is  usually 
experienced  should  they  enter  the  zone  of  sensibility  formed  by 
the  cementum  which  composes  the  end  of  the  root,  of  the  slightest 
symptom  of  which  the  patient  should  be  instructed  to  instantly 
inform  the  operator.  The  probe-like  points  of  these  drills  do  not 
cut,  but  simply  guide  the  drills  and  confine  them  to  the  line  of  the 


Sectional  view  of 
an  inferior  molar 
decayed  on  the  pos- 
terior   approximal 


should  be  removed 
to  facilitate  en- 
trance to  the  pulp- 
chamber. 


ill 


Plate  IV. — Figs.  1  and  2  represent  the  superior  and  inferior  teeth  in  trans- 
verse section  through  the  base  of  the  pulp-chamber  in  the  crown,  showing  the 
entrance  to  the  root-canals. 

Figs.  3  and  4  represent  the  superior  and  inferior  teeth  in  transverse  section 
through  the  root-canals  as  they  diverge  from  the  pulp-chamber. 

aa,  bb,  cc,  dd,  ff,  dd,  and  ee,  Figs.  3  and  4,  show  the  relative  shapes,  whether 
circular,  oval,  or  flattened,  of  the  root-canals  in  the  teeth  they  severally  represent. 


Plate  IV. 


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17 


13  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

canal.  They  should  be  gently  given  a  slight  forward  and  quick 
backward  motion  in  the  canal,  and  treated  more  as  reamers  than 
drills.  The  occasional  quick  withdrawal  of  the  drill  from  the  canal 
during  the  process  of  drilling  will  aid  removal  of  the  debris.  The 
depth  to  which  a  canal  may  be  enlarged  or  reamed  is  regulated 
by  its  actual  length  and  the  above-mentioned  conditions,  and  the 
diameter  of  the  enlargement  by  the  shape  and  dimensions  of  the 
root. 

The  use  of  these  drills  is  condemned  by  some  for  reasons  which 
are  fairly  attributable  to  their  careless  or  improper  employment, 
but  they  are  indorsed,  in  experienced  hands,  for  their  adaptability 
to  the  work  under  consideration.  They  should  be  frequently 
sharpened  with  a  suitably  shaped  piece  of  Arkansas  stone. 

The  Palmer  root-canal  excavators  also  will  be  found  serviceable 
to  open  up  a  canal  and  enlarge  it  in  accordance  with  its  original 
shape.  While  the  Gates-Glidden  drills  are  serviceable  for  the 
work  described,  the  use  of  Donaldson  broaches  is  safest  and  most 
effective  in  the  upper  portion  of  the  canal,  especially  in  those  of 
very  small  caliber. 

A  75  per  cent,  aqueous  solution  of  sulfuric  acid  carried  on  a 
platinum  probe,  then  placed  in  the  canal  and  at  first  pumped  into 
it  with  a  smooth  broach,  is  most  effective  as  an  aid  in  opening 
up  very  small  canals  or  those  partly  closed  by  calcification.  In 
the  former  case  the  acid  softens  the  dentin  of  the  sides  of  the 
canal  so  that  the  friction  of  a  smooth  broach  will  materially  en- 
large it;  in  the  latter,  in  addition  to  this  effect,  it  decomposes  the 
calcified  contents  of  the  canal.  This  enlargement  of  the  canal 
with  the  smooth  broach  will  usually  admit  of  the  introduction  of 
a  Donaldson  barbed  broach,  first  small,  then  large,  by  which  the 
canal  can  be  much  more  rapidly  enlarged.  Canals  by  this  method 
can  almost  invariably  be  safely  opened  and  enlarged  to  the  apex, 
and  when  so  opened  they  are  thoroughly  divested  of  organic 
matter  by  the  action  of  the  acid. 

The  moderate  reaming  of  a  root-canal  not  only  simplifies  the 
operation  of  filling,  but  also  opens  up  the  ends  of  the  tubuli  and 
facilitates  the  permeation  of  antiseptic  agents. 

Treatment  and  Disinfection — Pulpless  teeth  are  presented  for 
treatment  in  one  of  the  four  f ollowing  conditions : 

1.  Where  healthy  or  non-putrescent  pulps  have  just  been 
extirpated  from  the  canals. 


PULPLESS  TEETH. 


19 


2.  Where  on  opening  into  the  pulp-chamber  it  is  found  empty 
and  dry,  with  the  pulp  mummified  or  calcified  in  the  root-canals, 
and  the  root  externally  in  a  healthy  condition. 

3.  Where  the  pulp  is  found  diseased  or  in  a  putrescent  condi- 
tion. 

Fig.  6. 


4.  Where  alveolar  abscess-  is  present  and  a  septic  condition  of 
the  canals  and  dentin  exists. 

In  the  first  and  second  classes  the  treatment  should  be  directed 
to  assuring  a  continuance  of  the  existing  aseptic  condition,  and 
as  immediately  as  possible  the  filling  of  the  canal;  in  the  third 
and  fourth  classes,  to  bringing  about  an  aseptic  condition  by  dis- 
infection and  sterilization,  and  making  certain  of  its  future  main- 


Fig.  7. 


tenance,  including  incidentally  the  cure  of  any  existing  disease 
of  the  external  membrane  or  of  the  alveolus.    „ 

In  cases  of  the  first  and  second  classes,  if  possible,  saliva  should 
be  excluded  from  the  pulp-chamber  and  canals  during  their  entire 


20 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


preparation  and  filling.  If  necessary,  hydrogen  peroxid  can  be 
used  instead  of  water.  The  instruments  should  be  sterilized, 
and  the  broaches,  if  serrated,  had  better  be  new.  In  the  third  and 
fourth  classes,  exclusion  of  saliva  or  water  is  not  necessary  in  the 
preliminary  work  on  the  canal;  water  may  be  freely  used  until 
the  process  of  disinfection  and  sterilization  is  commenced.  Then 
and  thereafter  its  entrance  must  be  prevented.  To  this  end  the 
rubber-dam  should  be  applied  if  practicable.  When  it  is  not,  as 
frequently  occurs  with  roots  and  teeth  badly  affected  with  cervical 
decay,  other  means  of  keeping  out  moisture  should  be  resorted  to. 
In  such  cases,  during  each  interruption  in  the  operation  the 
entrance  to  the  canal  should  be  filled  with  absorbent  cotton  satu- 
rated with  a  suitable  essential  oil  or  antiseptic  fluid,  the  saliva 
being  thus  excluded. 

After  the  canal  has  been  properly  opened  up  and  its  contents 
removed,  it  may  be  washed  out  with  hydrogen  peroxid,  and 
wiped  out  with  absorbent  cotton.  The  use  of  sodium  peroxid  is 
recommended  by  Dr.  Kirk  at  this  stage  to  open  up  the  ends  of 
the  tubnli.  The  next  procedure  is  to  secure  as  thorough  a  state  of 
dryness  in  the  pulp-chamber  as  is  possi- 
ble by  forcing  into  it  with  a  hot-air  syr- 
inge (Fig.  6  and  Fig.  7),  air  at  a  tem- 
perature higher — as  it  leaves  the  nozzle 
— than  is  comfortable  for  the  finger.  A 
root-canal  drier,  with  the  end  tapered  as 
line  as  a  broach  at  the  point,  is  then 
introduced  into  the  canal.  The  writer 
prefers  the  form  in  which  the  point  is 
made  of  silver  and  the  bulb  portion  of 
copper  (Fig.  8).  As  silver  possesses  re- 
markable properties  as  a  thermal  con- 
ductor, the  heat  is  transmitted  to  the 
point  of  the  probe  very  rapidly.  The 
probe  being  inserted  as  far  as  possible  up 
the  canal  (Fig.  9),  the  patient  is  directed 
to  raise  the  hand  as  a  signal  should  the 
ii eat  cause  pain,  when  the  probe  must  be 
moved  up  and  down  or  withdrawn  for 
a  moment.  This  procedure,  following  the  previous  application  of 
the  hot  air  with  the  syringe,  evaporates  the  moisture  and  aids  the 


Fro.  8. 


Fig.  !). 


PVLPLESS  TEETH.  21 

escape  of  any  gases  present  in  the  root-canals  and  the  open  ends 
of  the  tubuli.  The  point  of  the  root-canal  drier  acts  as  a  sterilizer, 
and  may  be  applied  so  hot  as  to  carbonize  any  organic  matter  which 
it  reaches  in  the  end  of  the  canal,  and  a  portion  of  this  can  be  re- 
moved each  time  on  its  point.  As  the  silver  point  can  be  tapered 
as  small  as  the  finest  broach,  canal-contents  impossible  to  remove 
may  be  reached  and  rendered  inert. 

In  cases  of  the  third  or  fourth  class,  sepsis  being  present,  the 
heat  is  very  serviceable,  as  it  aids  the  escape  of  gases  from  the  canal 
and  dentin  and  acts  as  a  germicide.  When  in  this  dry  and  heated 
condition,  the  dentin  is  in  the  best  possible  state  for  the  application 
of  antiseptic  agents. 

Use  of  Antiseptics. — Great  diversity  of  opinion  exists  as  to  the 
suitability  of  various  antiseptics  to  the  needs  in  treating  tooth- 
structure,  their  effectiveness  and  permanency  when  so  used,  singly 
or  in  combination,  and  their  adaptability  to  various  conditions. 
Many  of  the  antiseptics  in  common  use  being  coagulants  of  albu- 
min obstruct  the  dentinal  tubuli,  and  their  diffusibility  through  t lie 
dentin  is  consequently  self -limited.  To  this  class  belong  carbolic 
acid,  creasote,  and  the  like.  They  are  not  entirely  non-diffusible 
in  devitalized  dentin  or  cementum,  as  decomposition  effects  ele- 
mentary changes  in  the  contents  of  the  tubuli,  but  their  action  is 
slow  and  limited  as  compared  with  that  of  some  other  agents,  as 
the  essential  oils.  They  are  also  irritant,  and  unsuitable  in  cases 
where  an  acute  or  chronic  inflammation  of  the  peridental  mem- 
branes is  to  be  treated. 

The  essential  oils,  which  are  non-coagulative  in  their  action,  have 
greater  diffusibility,  and,  according  to  Miller,  Harlan,  and  others, 
possess  much  greater  antiseptic  power  than  was  formerly  attributed 
to  them.  Acidulated  solutions  of  mercury  bichlorid,  hydrogen 
peroxid,  sodium  peroxid, — especially  in  preliminary  treatment, — 
and  preparations  of  iodin  that  exert  a  chemical  action  and  retain 
their  antiseptic  properties  for  a  great  length  of  time  are  the  most 
suitable. 

The  selection  of  antiseptic  agents  is  therefore  important,  and 
the  choice  is  indicated  by  the  conditions  presented  in  a  pulpless 
tooth.  Teeth  from  which  a  healthy  pulp  has  just  been  extracted, 
or  in  which  the  canal  is  aseptic,  differ  in  their  requirements  from 
those  in  which  sepsis  of  dentin  or  diseased  or  putrescent  pulps  are 
present. 


22  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

In  the  first-mentioned  conditions,  favorable  results  usually 
follow  root-filling,  with  or  without  antiseptic  treatment,  the  advan- 
tage of  the  antiseptic  agent  in  the  canal  being  only  to  better  assure 
the  continuance  of  the  state  of  asepsis.  When  a  healthy  pulp  has 
just  been  extirpated,  and  immediate  root-filling  is  practiced,  the 
use  of  carbolic  acid,  creasote,  or  solution  of  zinc  chloric!  is  indi- 
cated. The  minute  fibrous  connections  with  the  walls  of  the 
canal  and  the  vessels  at  the  apical  foramen  are  severed,  and  the 
action  of  an  escharotic  antiseptic  agent  is  in  fact  required,  as  it 
acts  as  a  coagulant  and  instantly  seals  up  the  ends  of  the  tubuli. 
If  immediate  root-filling  is  not  to  be  practiced,  then  the  prescrip- 
tion of  such  agents  as  the  essential  oils,  with  aristol  or  iodoform, 
seems  more  suitable,  as  by  their  action  a  sort  of  mummification  of 
the  non-vital  organic  matter  follows.  Moreover,  the  oils  possess 
advantages  over  the  coagulants  in  that  they  are  not  miscible  in 
water,  and  are  less  easily  eliminated.  Their  use  will  tend  better 
to  perpetuate  an  aseptic  condition. 

In  the  second  class  of  cases, — teeth  with  sepsis  of  dentin  or 
having  diseased  or  putrescent  pulps, — we  need  the  intervention  of 
agents  which  will  not  only  destroy  ptomains,  but  which  will  exert 
a  chemical  action  on  sulfuretted  hydrogen  and  ethereal  ammoniacal 
gases,  the  products  of  putrefaction,  and  entirely  eliminate  them. 
On  this  depends  the  successful  treatment  of  such  cases,  as  the  ex- 
pansion and  pressure  of  tbese  gases  are  a  certain  cause  for  constant 
peridental  inflammation,  and  so  long  as  they  are  present  in  the 
slightest  degree  in  a  canal  it  is  in  an  unsuitable  condition  to  be 
closed.  Carbolic  acid,  creasote,  or  the  essential  oils,  under  such 
circumstances  exert  no  chemical  action  on  these  gases,  merely  dis- 
guising their  odor,  though  it  is  true  that  by  repeated  dressings  of 
cotton  saturated  with  one  of  these  agents  the  gases  are  absorbed 
by  the  cotton  and  slowly  eliminated. 

What  is  required  is  the  action  of  an  agent  whose  elements  pos- 
sess an  affinity  for  the  gases,  and  so  will  immediately  decompose 
them,  forming  new  combinations  and  entirely  changing  their 
character. 

In  accordance  with  these  principles,  iodin  is  indicated  as  prefer- 
able in  practice  to  the  other  agents  mentioned.  Its  effects  are 
best  obtained  from  some  one  of  the  preparations  now  in  use, — 
aristol,  for  instance, — whose  odor  is  entirely  unobjectionable,  in  a 
strong  solution  in  one  of  the  essential  oils.    In  the  writer's  practice 


PVLPLE88  TEETH.  23 

the  oils  of  cloves,  cassia,  and  eucalyptus  are  favored  for  this  pur- 
pose, the  first  named  being  reckoned  more  sedative  in  its  action 
than  the  others.  He  makes  it  a  point  to  flood  the  canal  with  the 
solution,  thereby  to  some  extent  permeating  the  dentin  as  well  as 
the  cementum  at  the  apex.  A  more  complete  saturation  can  be 
accomplished  by  drying  and  heating  the  dentin  and  applying  the 
solution  a  second  time,  or  by  filling  the  canal  with  cotton  saturated 
with  it,  hermetically  inclosing  it,  and  letting  it  so  remain  for  a 
day  or  two. 

As  aristol,  oil  of  cloves,  and  cassia  have  a  tendency  to  slightly 
discolor  dentin,  their  use  should  be  confined  to  the  extremity  of 
the  root-canal,  and  plain  oil  of  eucalyptus  or  myrtol  used  in  the 
orifice  and  coronal  section  of  the  tooth  where  maintenance  of  the 
natural  color  of  the  crown  has  to  be  considered  in  an  operation. 

The  disadvantage  of  immediate  root-filling  is  that,  should  some 
fragment  of  the  pulp  remain  in  the  extremity  of  the  canal,  it  fails 
to  receive  the  benefit  accruing  from  the  reapplication  of  antisep- 
tics, which  would  better  assure  its  inertness  by  mummification. 

There  is  such  a  thing  as  over-treatment, — an  unnecessarily 
frequent  renewal  of  antiseptic  dressing  in  root-canals,  thereby 
aggravating  or  producing  irritation  of  the  pericementum  at  the 
apex  of  the  root.  Such  cases  may  be  relieved  by  washing  out 
the  canal  with  alcohol  and  then  applying  the  alcohol  on  the  dress- 
ing, instead  of  the  agents  previously  employed,  until  the  inflamma- 
tion subsides. 

The  dressing  of  root-canals  is  best  performed  with  the  aid  of 
the  ordinary  smooth,  flexible  rectangular  broaches;  also  root-canal 
dressers,  such  as  the  How.  The  form  of  these  instruments  permits 
fibers  of  cotton  to  be  easily  wound  around  them  lengthwise  and 
over  the  point  in  one  connected  mass.  When  the  cotton  is  intro- 
duced in  the  canal,  it  is  retained  on  and  carried  forward  by  the  in-, 
strument,  which,  when  withdrawn,  leaves  the  cotton  in  position  in 
the  canal  in  the  form  of  a  cone  or  tampon  that  will  favor  the.  escape 
of  gases,  and  it  may  still  be  easily  removed^at  any  time.  After 
one  or  more  treatments  in  the  manner  described,  between  which, 
if  interspersed  by  intervals  of  time,  the  antiseptic  agents  must  be 
hermetically  sealed  in  the  cavity  with  gutta-percha,  the  canal  is 
dried  and  the  foramen  closed. 

Closure  of  the  Apical  Foramen  and  Filling  of  the  Canal. — 
The  object  of  root-canal  filling  is  the  maintenance  of  an  aseptic 


24  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

condition  in  a  sterilized  root-canal  by  hermetically  closing  it  at 
both  the.  apical  foramen  and  the  orifice,  and  thus  preventing  its 
infection  by  the  entrance  of  either  fluids  or  gases.  Gutta-percha 
and  zinc  oxychlorid  are  generally  accepted  as  most  suitable  for 
the  purpose.  Either  gutta-percha  in  the  form  of  chloro-gutta- 
percha,  or  zinc  oxychlorid  mixed  thin,  can  be  pumped  or  placed 
in  the  extreme  end  of  the  canal  with  the  aid  of  a  broach  or 
fine-pointed  probe.  This  is  one  of  the  advantages  that  commend 
the  use  of  these  materials.  When  the  chloro-gutta-percha  has  been 
placed  in  the  apex,  the  remainder  of  the  canal  can  be  filled  with  the 
prepared  cones  of  solid  gutta-percha  until  no  more  can  be  inserted. 
A  current  of  hot  air  should  then  be  thrown  on  the  protruding  ends 
of  the  cones  at  a  temperature  sufficient  to  soften  them  and  warm 
the  dentin,  when  they  should  be  gently  pressed,  but  not  suddenly 
pushed,  up  in  the  canal.  A  slight  twinge  of  pain  to  the  patient 
will  usually  be  the  signal  of  their  complete  impactment  in  the 
canal.  The  solid  gutta-percha  absorbs  what  little  chloroform  was 
present  in  the  chloro-gutta-percha,  and  the  heat  also  aids  its 
evaporation,  so  that  the  shrinkage  so  often  urged  as  an  objection 
against  the  use  of  chloro-gutta-percha  is  reduced  to  a  minimum. 

An  advantage  possessed  by  zinc  oxychlorid  over  other  mate- 
rials is  its  antiseptic  qualities;  its  disadvantage,  the  difficulty  at- 
tending its  removal  from  the  extremity  of  the  canal  should  super- 
vening conditions  require  it.  For  this  reason  the  apex  and 
extremity  of  the  canal  may  be  filled  with  gutta-percha,  and  then 
the  orifice  and  pulp-chamber  with  oxychlorid.  This  combination 
forms  an  ideal  root-canal  filling,  as  the  oxychlorid  hermetically 
closes  the  orifice  of  the  canal  and  prevents  its  infection  from  the 
oral  cavity.  When  metallic  points  of  lead  and  copper  shaped 
to  fit  are  used  to  fill  root-canals,  unless  a  small  quantity  of 
zinc  oxychlorid  is  placed  in  the  extremity  or  on  the  point  used, 
the  complete  closure  of  the  canal  is  doubtful.  The  use  of  cotton 
as  a  filling  in  root-canals  is  to  be  condemned,  unless  it  is  sterilized1 
or  iodoformized  and  saturated  with  chloro-gutta-percha  or  zinc 
oxychlorid  previous  to  insertion.  Asbestos  is  given  preference 
to  cotton  by  some.     Tin  or  gold  foil  is  difficult  to  insert  without 

1  Cotton  may  be  sterilized  by  immersing  it  for  a  time  in  a  saturated  solu- 
tion of  iodoform  in  ether,  and  then  drying.  It  should  be  kept  in  a  tightly- 
corked  bottle.  When  this  plan  is  followed,  the  odor  of  iodoform  is  avoided 
in  the  operating-room. 


PULPLESS  TEETH. 


25 


leaving  vacuoles.  Paraffin  combined  with  a  small  quantity  of  aris- 
tol,  as  a  material  to  fill  root-canals,  has  been  suggested  by  Dv. 
Kirk,  especially  after  the  use  of  sodium  peroxid.  This  agent,  being 
a  most  active  solvent  of  albuminous  matter,  in  a  measure  frees  the 
ends  of  the  tubuli  or  a  canal  of  their  organic  contents,  a  condition 
favorable  for  the  use  of  paraffin.  Paraffin  is  aseptic  and  melts  at 
a  low  temperature,  and  with  a  heated  root-canal  drier  can  be 
flowed  into  the  ends  of  the  tubuli  or  into  a  minute  canal  not  con- 
sidered safe  to  open  up  extensively.  Balsamo  del  Deserto  can  be 
used  in  the  same  manner. 

Ordinary  gutta-percha  should  be  used  to  close  a  foramen  when 
an  abscess  lias  just  been  treated  by  injecting  through  it.  The 
length  of  the  canal  should  be  measured  with  a  probe,  and  gaged 
with  a  small  perforated  disk  of  rubber-dam  slipped  upon  the 
instrument.  The  gutta-percha  should  then  be  carried  to  position 
on  the  point,  allowance  being  made  for  the  displacement  of  the 
instrument.  As  oil  of  eucalyptus  is  a  solvent  of  gutta-percha,  the 
application  of  this  oil,  alone  or  in  combination  with  iodoform  or 
aristol  to  the  surface  of  the  gutta-percha,  is 
recommended  in  the  final  treatment,  as  better 
adhesion  to  the  walls  of  the  canal  is  thus  ob- 
tained. 

Ample  room  should  be  left  in  any  root- 
canal  which  is  to  receive  the  post  of  a  crown, 
as  any  part  of  the  canal  not  occupied  by  the 
post  will  be  filled  by  the  retaining  material. 

"When  a  post  has  been  fitted  to  a  canal  pre- 
vious to  the  closure  of  the  foramen,  the  point 
of  it  may  often  be  utilized  to  aid  in  the  final 
pressing  of  the  gutta-percha  to  place  by  warm- 
ing the  post  and  wiping  the  point  with  oil  of 
cloves  to  prevent  adhesion  of  the  gutta-percha. 

"When  zinc  oxychlorid  is  used,  the  foramen 
should  preferably  be  first  closed  with  a  small  quantity  of  either 
solid  gutta-percha  or  the  chloroform  solution  of  it,  to  avoid  the 
accidental  protrusion  of  the  oxychlorid,  which  is  then  pumped 
up  the  canal,  and  the  post  inserted.  "When  the  cement  is  about 
half  set,  the  post  is  seized  with  pliers  and  withdrawn  and  not  again 
inserted  until  the  cement  is  perfectly  set.  In  this  manner  an  oxy- 
chlorid socket  is  formed  into  which  the  post  will  accurately  fit. 


G,  Gutta-percha. 
0,  Oxychlorid. 
P,  Post. 


26  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

(See  Fig.  10.)     The  same  can  be  done  with  the  post  of  a  finished 
crown. 

A  pulpless  tooth  presented  for  crowning,  the  roots  of  which 
have  been  treated  and  filled  in  some  previous  operation,  should 
be  carefully  examined.  If  any  doubt  is  entertained  as  to  its 
hygienic  condition  it  should  receive  the  antiseptic  treatment  above 
described,  as  the  ultimate  success  of  crown-work  depends  largely 
upon  the  thoroughness  of  these  preliminary  operations. 


CHAPTER    IV. 

Chronic  Alveolar  Abscess, 
the  usual  forms— alveolarotomy— amputation  of  the  apex  of 

A  ROOT. 

Many  teeth  and  roots  presented  for  crown-work  are  affected 
with  chronic  alveolar  abscess.  A  general  description  of  an  effec- 
tive method  of  treatment  is  therefore  properly  associated  with  a 
discussion  of  the  subject. 

The  cause  of  chronic  alveolar  abscess  will  be  found  in  a  con- 
tinuation of  those  conditions  which  originally  produced  the  acute 
form.  The  tooth  or  root  being  pulpless,  septic  gases,  generated 
by  the  decomposition  of  organic  matter  in  the  root-canal  and  in 
the  tubuli  of  the  dentin,  find  an  outlet  through  the  open  foramen 
into  the  apical  space,  causing  pericementitis  and  formation  of  pus. 
The  general  treatment  consists  in  the  removal  of  all  septic  matter 
and  gases  from  the  root-canal  and  dentinal  tubuli,  the  destruction 
of  the  pus-sac,  the  application  of  suitable  therapeutic  agents,  and 
the  adoption  of  measures  to  prevent  further  formation  of  pus. 

The  Usual  Forms. — Chronic  alveolar  abscess  is  usually  found 
in  the  following  forms :  First,  abscess  with  a  fistulous  opening  in 
the  gum,  and  accessible  through  the  root-canal  and  foramen  of  the 
root.  Second,  abscess  with  fistulous  opening,  but  not  accessible 
through  the  apical  foramen.  Third,  abscess  from  which  pus  dis- 
charges through  the  apical  foramen  and  root-canal,  with  no  open- 
ing through  the  gum. 

In  the  treatment  of  abscess  of  the  first  form,  the  canal  should 
be  enlarged  as  described  in  the  treatment  of  pulpless  teeth,  and 
the  foramen  opened,  if  possible,  with  a  smooth  broach  without 
the  use  of  a  drill.  Aromatic  sulfuric  acid,  on  cotton,  placed  in 
the  end  of  the  canal  for  a  day.  will  usually  open  up  the  finest 
foramen.  A  small  quantity  of  75  to  90  per  cent,  aqueous  solution 
of  sulfuric  acid  pumped  into  the  extremity  of  the  canal  will  often 
enable  a  broach  to  instantly  effect  a  passage.  Tepid  water  is  then 
forced  through  the  foramen  with  a  fine-pointed  syringe  (Fig.  11) 


28  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

introduced  well  up  the  canal,  and  packed  in  with  gutta-percha; 
or  it  may  be  pumped  up  with  cotton  on  a  broach  until  it  passes 
into  the  abscess  and  out  through  the  fistula.  Hydrogen  peroxid 
is  next  used  in  the  same  manner.  Aromatic  sulfuric  acid  may  also 
be  injected  through  the  fistulous  opening  into  the  abscess. 

In  abscesses  of  the  second  form,  where  it  is  impracticable  to 
treat  through  the  foramen,  the  canal  should  be  thoroughly  disin- 
fected, and  a  direct  opening  into  the  abscess  effected  by  the  track 
of  the  fistula,  enlarging  it  when  necessary.  The  abscess  should 
then  be  thoroughly  injected  with  hydrogen  peroxid,  and  after- 
ward with  aromatic  sulfuric  acid,  by  introducing  the  fine  point 
of  a  syringe  into  its -deepest  parts.  The  fistula  must  be  kept  open 
while  treatment  is  conducted  by  inserting  in  it,  at  each  injection, 
Fig.  11.  a  strand  of  twisted  cotton  saturated 

with  oil  of  cloves,  the  patient  being 
directed  to  remove  it  in  a  few  hours, 
or  the  next  day,  for  which  purpose 
the  end  should  be  left  protruding. 
When  the  apical  foramen  is  open,  one 
injection  through  it  is  frequently  suffi- 
cient to  cure  an  abscess;  but  when  the 
foramen  is  closed  and  the  abscess  is 
treated  through  the  gum,  several  in- 
jections are  generally  necessary  and 
the  result  not  positive. 

In  case  of  "blind  abscess,"  the  third 
form,  first  open,  clean,  and  disinfect 
the  canal,  and  enlarge  the  foramen 
with  sulfuric  acid  and  Donaldson 
broaches,  so  that  the  largest  sizes  will  pass  freely  into  the  abscess. 
Through  the  enlarged  foramen  inject  and  wash  out  the  cavity  of 
the  abscess — at  first  daily — with  hydrogen  peroxid.  Insert  a 
small  probe  in  the  canal,  pack  the  orifice  with  gutta-percha,  press 
on  the  gutta-percha,  and  withdraw  the  probe.  The  aperture  left 
by  the  probe  furnishes  a  small  vent.  Continue  this  line  of  treat- 
ment until  evidence  of  suppuration  ceases,  then  temporarily  pack 
the  canal  with  cotton  slightly  moistened  with  oil  of  cloves  or  any 
other  of  the  suitable  essential  oils,  seal  the  orifice  of  the  canal,  and 
temporarily  fill  the  cavity.  Should  the  indications  appear  favorable 
on  the  removal  of  this  dressing,  or  any  subsequent  one  similarly 


CHRONIC  ALVEOLAR  ABSCESS. 


29 


Fig.   L2. 


Fig.  13. 


inserted,  close  the  foramen  with  a  cone  of  gutta-percha,  placed  in 
position  gently  so  as  to  avoid  protrusion  into  the  apical  space  or 
causing  pressure. 

This  method,  if  skilfully  practiced,  will  usually  effect  a  cure  of 
this  troublesome  form  of  abscess.  Should  this  treatment  fail,  an 
opening  through  the  gum  into  the  abscess  must  be  obtained,  with 
a  lance  and  drill,  and  the  same  course  pursued  as  in  the  first  form 
of  abscess. 

Alveolarotomy. — For  this  operation  the  length  of  the  root  and 
position  of  the  apex  should  be  first  accurately  determined.  This 
is  best  done  by  introducing  a  broach  with  a  hook  point  through 
the  canal  and  foramen  into  the  abscess  and  then  slowly  withdraw- 
ing it.  In  the  withdrawal,  the  hook 
by  catching  on  the  apex  shows  both 
the  position  and  the  length  of  the 
root  (Fig.  12). 

A  small  pellet  of  gutta-percha  or 
a  little  disk  of  heavy  rubber-dam 
placed  on  the  broach  at  the  point 
where  it  enters  the  root  or  tooth,  as 
shown  at  A,  Fig.  12,  will  form 
an  accurate  gage.  After  the  with- 
drawal of  the  broach  a  straight  fine 
probe  is  passed  up  the  canal  through 
the  foramen  into  the  abscess  and  left 
there  in  position,  the  exposed  por- 
tion (A,  Fig.  13)  fairly  indicating 
the  direction  in  which  the  root 
points,  and  should  no  considerable  curve  exist  toward  the  apex, 
the  line  in  which  the  abscess  cavity  is  most  likely  to  be  found.  The 
marked  broach  is  then  placed  externally  with  its  shank  exactly 
parallel  with  the  probe  in  the  canal  (see  B,  Fig.  13),  and  the  line 
of  the  broach  and  more  especially  the  location  of  the  hook  point 
marked  on  the  gum  with  carbolic  acid.  A  few  shreds  of  cotton 
closely  twisted  around  the  broach,  especially  at  the  point,  will  aid 
in  carrying  and  holding  the  acid.  In  this  manner  the  line  of  the 
root  and  the  position  of  the  end,  allowing  for  a  slight  curve  towTard 
the  apex,  can  be  located  within  a  small  fraction  of  an  inch,  and 
the  cavity  of  the  abscess,  which  may  be  a  little  to  the  right  or  left 
of  the  point,  determined  with  sufficient  accuracy.    The  membrane 


30 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  14. 


at  the  spot  marked  as  over  the  end  of  the  root  is  then  punctured 
and  entrance  to  the  end  of  the  root  and  apical  space  and  abscess 
effected  through  the  bone  with  a  small  spear-shaped  bur  and  spoon- 
shaped  excavators.  The  fine  probe  protruding  through  the  fora- 
men into  the  abscess  will  aid  in  locating  the  abscess  cavity  and 
apex  of  the  root.  The  membranes  may  be  anesthetized  with  an 
injection  of  a  5  per  cent,  solution  of  eucain  previous  to  the  opera- 
tion. A  more  definite  method  practiced  by  the  author,  in  cases  of 
very  long  roots,  is,  after  getting  the  length  of  the  root  with  the 
broach  as  previously  described,  to  introduce  a  flexible  straight 
probe  up  the  canal,  through  the  foramen  into  the  abscess.  The 
probe  is  removed,  warmed,  and  again  introduced, 
with  a  film  of  gutta-percha  placed  on  the  shank  to 
steady  and  indicate  its  exact  position.  The  broach 
indicating  the  length  of  the  root  is  placed  externally 
against  the  surface  of  the  gum,  over  the  root,  with 
its  shank  and  handle  parallel  to  the  shank  and 
handle  of  the  probe  in  the  canal.  Shanks  and 
handles  are  then  connected  with  a  piece  of  softened 
impression-compound,  the  compound  is  slightly 
chilled,  and  the  instruments  removed.  (See  Fig. 
14.)  If  on  removal  the  broach  and  probe  are  found 
not  to  be  exactly  parallel,  they  are  made  so. 

By  this  means  on  the  reinsertion  of  the  probe  in 
position  in  the  canal  doubt  is  removed  as  to  the 
location  of  the  apex  of  the  root,  as  it  is  not  possible 
to  always  positively  parallel  the  broach  and  probe 
while  the  latter  is  hidden  in  the  root-canal,  where 
also  it  is  often  far  from  being  steadily  fixed. 

In  these  cases,  curetting  of  the  cavity  of  the  abscess  and  apex 
of  the  root  is  most  effective,  but  the  removal  of  healthy  bone 
tissue  should  be  avoided  as  much  as  possible,  as  the  stability  of 
the  root  is  proportionately  impaired  thereby. 

An  entrance  into  the  apical  space  can  be  made  almost  pain- 
lessly in  the  following  manner,  as  described  by  Dr.  G.  V.  Black  :* 
"The  mucous  membrane  is  first  dried  at  the  point  at  which  it  is 
desired  to  make  the  opening,  and  napkins  are  so  placed  as  to 
keep  it  dry.     Then  a  plugging-instrument  with  fairly  sharp  ser- 


"Ameriean  System  of  Dentistry,"  vol.  i,  page  928. 


OHHONIC  ALVEOLAR  ABSCESS.  31 

rations  and  of  convenient  shape  is  selected.  The  point  of  this 
is  dipped  into  a  95  per  cent,  solution  of  carbolic  acid,  and 
a  drop  conveyed  to  the  mucous  membrane;  this  will  at  once  pro- 
duce a  white  eschar.  Then  a  slight  scratching  motion  with  the 
serrated  point  is  begun,  with  a  view  of  removing  the  tissue  that  is 
whitened.  This  is  continued  until  the  carbolic  acid  is  thick  with 
the  debris  of  the  tissue  torn  up,  then  it  is  dried  out  and  another 
drop  added,  as  before,  and  the  process  continued.  This  is  repeated 
as  often  as  may  be  necessary,  going  deeper  and  deeper  into  the 
tissue  in  the  desired  direction  until  the  bone  is  laid  bare.  Then 
a  fresh  drop  of  the  acid  is  placed  on  the  bone,  and  the  periosteum 
carefully  raised  over  a  sufficient  space;  then  with  a  sharp  chisel 
cut  through  to  the  peridental  membrane.  This  will  generally 
cause  some  pain  and  some  bleeding,  but  after  giving  a  little  time 
for  this  to  cease,  and  adding  more  of  the  acid,  the  apical  space  can 
usually  be  reached  without  difficulty.  No  blood  should  be  drawn 
at  any  time  during  the  operation,  except  in  penetrating  the  wall 
of  the  alveolus.  In  doing  this  no  tissue  is  removed  until  it  is 
anesthetized  by  the  carbolic  acid.  This  is  a  little  tedious,  but  it 
is  almost  painless,  and  the  general  effect  is  usually  better  than  by 
other  modes  of  penetrating  the  apical  space.  The  carbolic  acid 
has  the  effect  of  modifying  the  pain,  and  the  opening  left  does 
not  close  so  readily." 

A  period  of  entire  cessation  of  discharge  of  pus  is  to  be  con- 
sidered the  most  favorable  indication  of  successful  treatment. 

Thorough  disinfection  and  sterilization  of  the  dentin  and  root- 
canals  are  included  in  the  preliminary  treatment  of  alveolar 
abscess.  As  soon  as  the  treatment  is  followed  by  favorable  indi- 
cations, the  foramen  should  be  closed  while  the  fistula  is  yet  open. 
Any  further  treatment  considered  necessary  can  be  conducted 
externally  through  the  fistula.  This  may  be  facilitated  by  en- 
larging the  orifice  with  tents  of  cotton  saturated  with  oil  of  cloves. 
Enlargement  of  the  fistula  tends  to  encourage  the  process  of  granu- 
lation in  the  region  which  has  been  occupied  by  the  abscess,  espe- 
cially when  a  more  than  usual  necrosed  condition  of  the  bone 
requires  its  removal. 

After  the  abscess  has  been  cured,  the  root-canals  are  filled  as 
described  on  page  23. 

Aromatic  sulfuric  acid  is  a  powerful  astringent  and  germicide. 
It  will  be  found  most  useful  in  cases  where  a  slightly  necrosed 


32  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

state  of  the  wall  of  the  alveolus  exists.  Its  use  should,  however, 
be  limited,  and  in  subsequent  external  treatment  through  the 
fistula  some  of  the  other  therapeutic  agents  should  be  employed, 
as  the  hydrogen  peroxid,  or  the  essential  oils  or  carbolic  acid, 
alone  or  combined  with  one  of  the  preparations  of  iodin.1 

Injections  of  sulfuric  acid  in  the  region  of  the  mental  foramen 
should  be  made  cautiously,  and  it  should  not  be  applied  to  an 
abscess  bordering  on  the  antrum  until  the  operator  is  positively 
assured  that  the  abscess  does  not  open  into  that  cavity. 

Amputation  of  the  Apex  of  a  Root. — In  long-neglected  alveo- 
lar abscess,  the  pus-cavity  occasionally  involves  the  alveolus  in 
such  a  way  as  to  destroy  a  considerable  portion  of  the  pericemen- 
Fig.  15.        turn  of  the  end  of  the  root.    The  cementum  of  that 
part  is  consequently  devitalized,  and  the  portion 
of  the  root  affected  becomes  degenerated  in  struc- 
ture, and  saturated  with  septic  matter.     In  this 
condition  it  acquires  the   character  of  a  foreign 
substance,  proves  a  constant  source  of  irritation, 
and  defies  all  efforts  of  the  membranes  to  perfectly 
inclose  or  encyst  it. 

In  such  cases,  when  curetting  of  the  abscess  cav- 
ity and  end  of  the  root  has  failed,  amputation  of  the 
portion  of  the  root  which  is  denuded  of  pericemen- 
tum is  the  best  course  to  pursue.  An  opening  is 
made  in  the  soft  tissues  over  the  affected  part  in  the  manner  de- 
scribed on  page  29,  and  gradually  enlarged  with  a  tent  of  lint 
or  cotton  until  the  diseased  territory  is  fully  exposed  (Fig.  15), 
when  the  devitalized  end  of  the  root  and  any  necrosed  bone  in 
the  territory  are  removed,  and  the  end  of  the  root  smoothed. 
Only  enough  of  the  end  of  the  root  should  be  excised  to  thor- 
oughly remove  the  affected  part,  as  an  excess  will  proportionally 
lessen  its  stability  and  usefulness.  The  canal  should  be  filled 
solidly  with  gutta-percha  or  preferably  zinc  oxychlorid  previous 
to  the  amputation,  so  that  when  the  end  of  the  root  is  excised 
the  stump  will  be  left  smoothly  and  snugly  filled.  Cocain  can  be 
used  in  this  operation. 

1  For  an  extended  consideration  of  this  subject  the  reader  is  referred  to  Dr. 
J.  N.  Farrar's  articles  on  "Sulphuric  Acid  v.  Creasote  in  Treatment  of 
Alveolar  Abscess,"  commencing  in  Dental  Cosmos,  vol.  xx,  No.  7,  and  Dr. 
G.  V.  Black's  article  in  the  "American  System  of  Dentistry,"  vol.  i,  page  929. 


CHRONIC  ALVEOLAR  ABSCESS.  33 

The  orifice  of  the  cavity  in  the  gum  should  be  kept  open  and 
injected  daily  with  a  mild  antiseptic  solution  by  the  dentist  or 
patient  until  the  cavity  is  filled  by  granulation.  In  cases  where 
extensive  necrosis  of  the  alveolar  process  has  existed,  in  addition 
to  the  daily  injection  the  cavity  should  be  packed  with  a  suitable 
antiseptic  dressing.  Balsam  Peru  has  been  found  by  the  author 
to  be  a  suitable  agent  for  the  purpose,  as  it  assists  the  process  of 
granulation.  When  the  healing  process  is  completed,  crown-work 
can  be  proceeded  with. 

The  amputation  of  roots  requires  skill  and  experience,  and  had 
better  be  confined  to  the  front  teeth  or  those  with  a  single  root, 
except  in  the  hands  of  experts.  The  performance  of  this  opera- 
tion without  preliminary  treatment,  by  making  a  transverse  in- 
cision across  the  line  of  the  end  of  the  root,  is  to  be  condemned. 
The  hemorrhage  obstructs  the  view  of  the  parts  and  renders  liable 
the  removal  of  an  unnecessary  amount  of  tissue,  besides  it  in- 
creases the  severity  of  the  operation. 


CHAPTER    V. 


Shaping  Teeth  and  Roots  for  Crown-Work. 


PRINCIPLES  INVOLVED — PREPARATION  OF  TEETH  OR  ROOTS  FOR 
COLLAR  CROWNS,  AND  INSTRUMENTS  USED— FOR  READY-MADE 
PORCELAIN  CROWNS — SPECIAL  PREPARATION  OF  BADLY  DECAYED 
TEETH  OR  ROOTS. 

Principles  Involved. — The  principles  governing  the  shaping 

of  the  surface  of  a  natural  crown  or  root  for  any  style  of  artificial 

crown  with  a  collar  attachment  require  that  the  cervical  portion 

of  the  natural  crown  and  root  shall  be  given  a  form  that  has 

longitudinally  parallel  sides  gaged  to  the  line  of  the  periphery 

of  that  part,  and  that  any  of  the  coronal  section  present  below  it 

shall  be  reduced  at  least  sufficiently  in  size  to  come  within  this 

line.     Such  a  form  is  necessary  to  admit  of  a  perfect  adaptation 

of  the  collar. 

Fig.  16. 


Preparation  of  Teeth  or  Roots  for  Collar  Crowns, and  Instru= 
ments  Used. — The  coronal  section  of  a  natural  crown  to  be 
prepared  is  usually  first  ground  on  the  occluding  surface  with  as 
large  a  corundum-wheel  as  the  case  will  conveniently  admit 
(Fig.  1G).  Molars  and  bicuspids  for  all-gold  crowns  should  have 
enough  substance  removed  to  make  a  small  space  between  them 
and  the  antagonizing  teeth.  The  approximal  sides  of  the  cervix 
should  be  reduced  sufficiently  to  allow  a  free  space  between  the 
gold  collar  when  adjusted  and  the  cervices  of  approximal  natural 
teeth  or  artificial  crowns,  to  make  room  for  the  gum-septa.  The 
approximal  surfaces  are  removed  straight  from  the  cervical  border 
34 


SHAPING  TEETH  AXD  ROOTS  FOR  CROWN-WORK.  35 

to  the  occluding  surface,  using  corundum  or  carborundum  and 
rubber  disks  (Fig.  17),  straight-sided  or  cup-shaped,  to  get  the 
angle,  and  occasionally  thin  separating  files;  and  last  of  all,  as  in- 
jury to  the  approximal  teeth  is  then  more  easily  avoided,  the  labial 
and  palatal  portions,  for  which  small  corundum-points  (Fig.  18) 
and  wheels  are  best  adapted.    The  corners  are  then  rounded.     The 


Fig.  1; 


Fig.  18. 


cervical  portion  of  roots  for  collar  crowns,  which  includes  the 
junction  of  the  dentin  and  enamel,  is  trimmed  so  that  the  sides 
as  illustrated  at  A,  Fig.  19,  are  level  and  parallel  with  the  line  of 
the  root,  and  as  deep  as  the  collar  is  to  be  placed  (Fig.  20).  For 
this  work  small  corundum-points,  trimmers,  and  files  can  be  used. 


Fig.  19. 


Fig.  20. 


Fig.  21.        Fig.  22. 
i 


Ih 


n 


km    s   m 


I 


Fig.  23. 


§ 


1       I     * 


Trimmers  of  the  shapes  and  sizes  illustrated  in  Fig.  21,  preferably 
made  with  cross-cut  serrations,  in  the  ordinary  hand-piece  or  in 
the  right-angle  attachment,  will  easily  and  quickly  accomplish 
this.  Fig.  22  illustrates  another  style,  in  the  form  of  a  triangular 
pyramid,  which  can  be  used  as  a  scraper  in  a  hand-socket,  bracing 
the  hand  by  resting  the  thumb  on  the  adjoining  teeth.     The  points 


36 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


should  be  tempered  very  hard.  Files  and  serrated  scrapers  shaped 
as  shown  in  Fig.  23  are  useful  in  rounding  angular  portions.  A 
smooth  surface  should  be  given  the  cervix.  On  approximal  sides 
and  the  curves  to  the  other  sides,  medium  coarse  corundum  tape 
and  paper  disks  can  be  used  for  this  purpose. 

In  pulpless  teeth,  the  use  of  excising  forceps  should  be  avoided 
unless  the  parts  admit  of  it  without  serious  shock  to  the  root. 
The  best  method  of  amputation  is  to  make  a  succession  of  holes 
with  a  spear-shaped  drill  across  the  portion  to  be  removed,  and 
then  cut  between  the  holes  with  a  fissure-bur  or  corundum-disk, 
which  will  permit  of  easy  removal  of  the  part  (Fig.  24). 

In  preparing  incisors  and  cuspids  for  gold  collar  crowns  with 
porcelain  fronts,  where  the  pulp  is  to  be  preserved,  the  labial 
surface  and  incisal   edge  should   be  ground   down  as  much   as 


Fig.  24.     Fig.  25. 


Fig.  26. 


Fig.  27 


Fig.  28. 


Fig.  29. 


possible  without  exposing  the  pulp  or  subjecting  it  to  irritation; 
the  palatal  portion  at  an  angle  from  the  cervical  border  to  the 
incisal  edge,  enough  to  level  its  prominences  of  contour  and  form 
a  slight  space  between  it  and  the  antagonizing  teeth  (Fig.  25). 
Pulpless  incisors  and  cuspids  should  be  prepared  by  grinding  the 
labial  face  to  the  gum-margin,  with  the  palatal  portion  slightly 
projecting  and  squared  off  to  the  inner  line  of  the  root-canal. 
(See  Fig.  20.)  Bicuspids  which  are  to  have  porcelain  fronts  are 
given  the  same  general  form  (Fig.  27).  In  preparing  the  roots  of 
incisors,  cuspids,  or  bicuspids,  it  is  advisable  to  let  the  labial  section 
of  the  end  of  the  root  project  slightly  beyond  the  gum-margin 
until  the  collar  has  been  fitted,  when  it  can  be  reduced. 

Bicuspids  and  molars  with  or  without  pulps,  for  all-gold  crowns, 


SHAPING  TEETH  AND  ROOTS  FOR  CIWYX^YORK. 


37 


should  have  as  much  of  the  natural  crown  left  as  possible  (Figs. 
28  and  29).  To  give  a  thimble-shaped  form  is  unnecessary  and  un- 
desirable. While  the  approximal  sides  might  very  slightly  taper 
toward  the  occluding  surface,  the  other  sides  should  be  as  nearly 
parallel  as  possible.  This  form  is  preferable  in  constructing  the 
crown  and  is  more  favorable  for  its  attachment. 

The  proportion  of  teeth  with  living  pulps  to  which  gold  crowns 
should  be  applied  is  small.  Such  cases  are  those  in  which  exten- 
sive decay  has  involved  considerable  of  the  coronal  section  of  the 
tooth  and  caused  more  or  less  calcification  of  the  pulp.  The 
preparation  of  these  cases,  of  which  Fig.  30,  a  bicuspid,  and  Fig. 
31,  a  molar,  are  typical,  consists  in  the  trimming  of  the  decom- 
posed enamel  at  the  approximal  sides,  a  moderate  reduction  of  the 
occluding  surface,  and  the  removal  of  enough  from  the  contour 
of  the  labial  and  palatal  surfaces  to  allow  the  edge  of  the  collar  to 


Fig.  30. 


Fig.  31. 


Fig.  32. 


n 


Kj 


Fig.  33. 


spring  over  and  be  closely  adjusted  at  the  cervical  section  just 
under  the  free  margin  of  the  gum.  Trimming  of  the  enamel 
for  the  purpose  of  deeply  imbedding  the  edge  of  the  collar  under 
the  gum-margin,  so  that  it  shall  closely  approach  the  perice- 
mentum, is  unnecessary,  either  for  the  purpose  of  retention  of 
the  crown  or  for  the  preservation  of  a  tooth  with  a  living  pulp. 
Irritation  of  the  pericementum  by  impingement  of  the  collar 
would  eventually  result  in  recession  of  the  membrane  and  ex- 
posure of  the  edge  of  the  collar.  Fig.  31  and  Fig.  33  show  the 
typical  bicuspid  and  molar  prepared  for  the  construction  of  the 
metallic  crowns,  the  natural  teeth  having  been  trimmed  and  the 
cavities  sterilized  and  filled  with  amalgam. 

Extremely  short  teeth  and  teeth  slightly  imbedded  in  the  tissues, 
as  many  third  molars  are,  do  not  require  as  much  shaping  as  long 
bicuspids  and  first  molars. 


38  CROWN-,  BRIDGE;  AND  PORCELAIN-WORK. 

It  should  be  borne  in  mind,  however,  that  unnecessarily  cut- 
ting away  the  enamel  and  dentin  of  teeth  with  living  pulps  leaves 
them  in  an  extremely  sensitive  condition,  and  is  likely  to  result 
subsequently  in  some  serious  lesion  of  the  pulp.  Slight  sensitive- 
ness, such  as  may  be  caused  by  excessive  shaping,  is  relieved  by 
drying  the  exposed  dentin  with  hot  air  and  applying  carbolic  acid 
two  or  three  times  as  required.  When  this  treatment  is  not  suffi- 
ciently effective,  a  temporary  cap  of  pure  gold,  about  No.  34  gage, 
can  be  quickly  constructed  and  cemented  on  with  gutta-percha. 
A  small  quantity  of  a  compound  of  oil  of  cloves,  carbolic  acid, 
and  chalk  (described  on  page  9)  placed  in  the  center  of  the  cap 
acts  as  a  sedative  and  remedial  agent. 

For  Ready=Made  Porcelain  Crowns,  roots  are  usually  ground 
level  with  the  margin  of  the  gum.  The  palatal  portion  of  the  end 
of  the  root  in  some  cases  may  be  allowed  to  project  a  trifle  beyond 
the  margin,  but  the  labial  aspect  should  be  trimmed  a  little  below, 
especially  on  the  front  teeth,  if  it  is  desirable  to  conceal  the  joint. 
The  root-canal  is  shaped  to  the  form  of  the  post  or  dowel  to  fit  it 
tightly.  (See  Part  II,  Chapter  III,  "Porcelain  Ready-Made 
Crown  System.") 

The  occluding  edges  or  surfaces  of  antagonizing  teeth  should 
be  removed  sufficiently  to  allow  ample  space  for  the  artificial 
crowns  or  to  favor  them  in  occlusion.  This  is  especially  necessary 
where  the  occluding  tooth,  in  the  absence  of  an  antagonist,  pro- 
jects beyond  the  proper  line  of  occlusion.  When  the  approximal 
teeth  crowd  against  and  overhang  the  end  of  a  root,  so  that  the 
space  for  the  artificial  crown  at  the  occluding  surface  is  narrower 
than  at  the  cervical  section, — measured  from  mesial  to  distal 
side, — the  sides  of  the  root  should  be  trimmed  so  as  to  give  a  free 
space  between  it  and  the  sides  of  the  approximal  teeth.  The 
approximal  teeth  may  also  be  pressed  away  by  packing  on  each 
side  of  the  root  wTith  gutta-percha,  or  a  small  portion  of  their  in- 
terfering surfaces  removed,  as  shown  in  typical  cases  in  Figs.  34 
and  35. 

Corundum  or  Vulcarbo  wheels  or  points  should  be  kept  wet 
and  cool  during  use  in  all  such  operations  in  the  mouth.  A  piece 
of  sponge,  held  against  the  wheel  with  clamping  pliers,  or  a  porte- 
polisher,  such  as  is  used  for  carrying  a  small  piece  of  wood  in 
cleaning  or  polishing  the  teeth,  answers  the  purpose  admirably, 
and  also  protects  the  tongue  and  cheek  from  injury. 


SHAPING  TEETH  AXD  ROOTS  FOR  CROWX-WORK. 


39 


Special  Preparation  of  Badly  Decayed  Teeth  or  Roots. — The 

temporary  exposure  of  the  end  of  a  root  or  of  the  cervical  por- 
tion of  a  crown  for  the  purpose  of  facilitating  or  simplifying  a 
crowning  operation,  especially  in  the  adaptation  of  a  collar,  is 
effected  by  inserting  in  the  pulp-chamber  or  the  root-canal  a  piece 
of  gutta-percha  large  enough  to  admit  of  a  portion  being  brought 
over  against  the  investing  membranes,  to  compress  them  for  a  day 
or  more.  In  some  cases  to  secure  attachment  for  the  gutta-percha, 
a  plug  of  wood  may  be  inserted  temporarily  in  the  root,  and  the 
gutta-percha  packed  around  it.  Roots  can  thus  be  exposed  to  the 
border  of  the  alveolar  process  if  desired.  In  bicuspids  and  molars, 
when  decay  extends  up  on  the  cervix  farther  than  will  the  edge 
of  the  artificial  crown  or  the  collar,  the  gums  should  be  pressed  up 
as  described,  the  decay  removed,  retaining-pits  made,  and  the 
cavity  filled  with  amalgam  shaped  to  the  contour  required  (Fig. 


Fig.  34. 


Fig.  35. 


30).  In  such  cases  the  amalgam  will  generally  be  in  close  prox- 
imity to  the  pulp  and  the  cavity  frequently  of  a  form  not  favor- 
able to  the  retention  of  the  filling.  To  avoid  irritation  from 
thermal  changes  and  better  retain  the  filling  a  moderately  thin 
mixture  of  oxyphosphate  may  be  first  placed  in  the  cavity,  the 
amalgam  then  pressed  into  it  and  the  oxyphosphate  forced  out, 
especially  at  the  margins  where  the  amalgam  must  be  brought 
into  direct  contact  with  the  tooth-structure.  In  incisors  and  cus- 
pids, when  decay  has  deeply  destroyed  a  portion  of  the  side  of  the 
root,  a  tight-fitting  tube  of  a  metal  to  which  amalgam  will  readily 
adhere,  and  of  such  size  as  to  admit  the  pin  of  the  crown,  may  be 
inserted  in  the  root-canal,  cemented  with  oxyphosphate,  and  the 
decayed  portion  restored  with  the  amalgam  on  the  side  of  the  root. 
The  post  of  the  crown  should  be  tapered  at  the  end,  and  inserted 


40 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


in  the  canal  as  deeply  as  possible  beyond  the  end  of  the  tube,  to 
gain  additional  strength  by  distributing  the  leverage  along  the 
whole  line  of  the  root. 

In  some  such  cases  a  better  method  is  to  fit  and  cement  a  pointed 
post  as  far  up  the  canal  as  it  can  be  safely  introduced,  leaving  the 
end  protruding  beyond  the  gum.  Then  shape  the  side  and  end 
of  the  root  with  amalgam  and  cap  with  a  platinum  and  porcelain 
jacket-crown  (Part  IV,  Chapter  VIII).  Fig.  37  shows  a  typical 
central  and  bicuspid  of  this  character. 

"When  an  incisor  or  cuspid  crown  post  is  to  be  inserted  and  the 
root-canal  is  enlarged  from  decay  or  excessive  reaming,  the  defect 
in  relation  to  the  post  of  the  crown  can  be  remedied  in  the  follow- 


Fig.  36. 


Fig.  37. 


Fig.  38. 


Fig.  38a. 


Fig.  39. 


Fig.  40. 


i 


ing  manner :  Fit  a  tapering  post  of  medium  size  with  the  point 
reaching  the  extremity  of  the  canal.  Close  the  foramen  with  a 
very  small  point  of  gutta-percha  so  that  it  will  not  interfere  with 
the  insertion  of  the  post.  Fill  the  canal  with  a  thin  mixture  of 
Ash  &  Sons'  "Rock  Cement"  (a  zinc  oxychlorid  which  sets  in 
three  minutes),  insert  the  post,  and  in  exactly  thirty  seconds  re- 
move it.  Instantly  wipe  off  the  post  and  reinsert  it.  The  tem- 
porary removal  of  the  post  prevents  the  adhesion  of  the  cement  to 
it,  so  that  when  the  cement  has  set  the  post  can  be  removed,  and 
you  have  a  close-fitting  socket  for  it. 

In  setting  a  gold  cap-crown  on  a  badly  broken-down  tooth  or 
root,  a  post  of  platinum  or  iridio-platinum  wire  should  be  fitted 


SHAPING  TEETH  AND  ROOTS  FOR  CROWN-WORK.  41 

to  the  root-canals  (Figs.  37,  38,  38a,  39,  and  40).  The  end  can 
be  bent  or  a  piece  of  gold  or  a  globule  of  gold  melted  to  it.  The 
post  should  then  be  barbed,  the  point  fastened  in  the  root  with 
a  little  oxyphosphate  or  zinc  oxychlorid,  and  the  crown  built 
down  about  two-thirds  its  length  with  a  quick-setting  amalgam, 
'to  be  shaped  when  hard  and  then  slightly  notched  to  furnish  a 
better  attachment  for  the  cement  with  which  the  cap  is  set.  Roll- 
ing the  wire  used  to  form  the  posts  under  the  flat  side  of  a  file 
before  using  will  uniformly  roughen  the  entire  surface  in  a 
manner  most  favorable  to  the  adhesion  of  the  cement.  Screws 
may  be  used  as  posts  to  support  the  amalgam,  but  cemented  posts 
are  preferable.  To  safely  retain  the  amalgam  in  position  during 
the  setting,  a  previously  made  and  properly  fitted  collar  of  thin 
German  silver  or  copper  plate,  not  over  Xo.  35  gage,  may  be  used. 
When  the  amalgam  has  set,  at  a  subsequent  sitting,  the  metal  can 
be  readily  stripped  from  its  surface,  which  should  be  dressed  down 
with  the  revolving  trimmers  evenly  to  that  of  the  surface  of  the 
root  or  crown.  In  such  cases  it  is  presumed  that  the  gold  cap  will 
entirely  cover  the  exposed  portion  of  the  amalgam. 


PART  II. 


ARTIFICIAL  CROWN-WORK. 


PAET  II. 


CHAP  TEE    I. 


Artificial  Crown-Work. 


FIRST  AUTHENTIC  ACCOUNT  OF  ARTIFICIAL  CROWN  OR  PIVOT  TEETH— 
THE  FIRST  PORCELAIN  PIVOT  TEETH — GOLD  PIVOT  TEETH— FIRST 
PORCELAIN  AND  GOLD  PIVOT  TOOTH  OR  CROWN— RICHMOND  PORCE- 
LAIN AND  GOLD  COLLAR  CROWN — THE  EARLIER  OPERATIONS- 
MORRISON  AND  BEERS  CROWNS— THE  FOSTER  AND  LAWRENCE 
CROWNS— THE  MACK  AND  HOWLAND-PERRY  CROWNS— THE  GATES- 
BONWILL  CROWN — THE  HOW  CROWN— THE  WESTON  CROWN — THE 
NEW  RICHMOND  PORCELAIN  CROWN— ADVANTAGES  CONFERRED  BY 
IMPROVEMENTS   IN  CEMENTS— CLASSIFICATION   OF   CROWN-WORK. 

First  Authentic  Account  of  Artificial  Crowns  or  Pivot  Teeth. 

— The  first  authentic  account  we  have  of  the  use  of  artificial 
crowns  or  pivot  teeth  is  given  by  Fauchard,  in  his  work  entitled 
"Le  Chirurgien  Dentiste  on  Traites  des  Dents/'  in  1728.  Fig.  41 
illustrates  the  crown  he  describes.  The  root  was  ground  level 
with  the  surface  of  the  gum,  the  root-canal  enlarged,  cleaned,  and 
filled  with  lead.  A  hole  was 
drilled  in  the  lead  and  the 
rough-surfaced  post  was  forced 
into  the  soft  metal  to  secure  it. 
The  other  end  of  the  post  was  Jja 
fastened  in  the  crown,  which 
was  either  a  natural  crown  or 
one  made  of  ivory. 

De  Chemant  described  the 
use  of  porcelain  for  the  construction  of  pivot  teeth  in  the  early 
part  of  the  last  century.  From  that  time  on  porcelain  has  been 
used  and  has  gradually,  for  the  most  part,  superseded  other  mate- 
rials for  the  construction  of  crowns. 

The  First  Porcelain  Pivot  Teeth.— The  porcelain  pivot  tooth 
or  crown  (Fig.  42)  was  the  form  used  for  many  years,  until  re- 

45 


Fig.  41. 

C 
I 


Fauchard's  "Dent  a  Tenon." 


46 


CROWN-,  BRIDGE-,  AND  FORCE  LAIN -WORK 


Fig.  42. 


Pivot  Tooth. 


cently.  When  first  introduced  it  was  attached  to  the  root  by 
means  of  a  hickory-wood  pin  or  pivot,  one  end  of  which  fitted 
the  hole  in  the  center  of  the  crown  and  the  other  that  of  the 
root-canal.  The  moisture,  by  swelling  the  wood,  securely  fastened 
the  pivot  in  both  tooth  and  root. 

It  was  found  that  the  wooden  pivot  in  time  caused  decay  of  the 
root,  and  was  liable  to  fracture  it  by  expansion;  it  also  affected 
the  breath.  These  objections  led  to  the  introduction  and  use  of  a 
gold  pivot  instead. 

Gold  Pivot  Teeth. — These  gold  pivots  were  variously  secured 
to  root  and  crown.  In  the  crown  the  pivot 
was  fastened  by  incasing  it  with  wood  or  by 
skilfully  flowing  a  little  gold  solder  around 
the  part  of  the  pivot  which  set  in  the  porce- 
lain, and  to  the  root  by  fitting  in  the  canal 
a  piece  of  hickory  and  inserting  the  pivot 
into  the  wood,  or,  by  twisting  fibers  of 
cotton  or  silk  around  the  post  and  pressing 
the  crown  to  position. 

First  Porcelain  and  Gold  Pivot  Tooth  or 
Crown. — The  porcelain  pivot  tooth  mounted 
by  these  methods  was  superseded  by  the 
use  of  a  plain  plate  porcelain  tooth,  backed  with  gold  and  sol- 
dered to  a  piece  of  plate  stamped  out  to  accurately  fit  the  end 
of  the  root  and  soldered  to  the  pivot  or  pin,  as  shown  in  Fig.  43. 
A  later  improvement  in  the  attachment  of  the 
crown  consisted  in  the  use  of  a  gold  tube,  which 
was  screwed  into  the  root  and  into  which  the  pivot 
was  tightly  fitted.  This  later  method  was  devised 
to  avoid  the  objectionable  features  connected  with 
the  use  of  wood.  The  transition  from  this  last- 
mentioned  method  to  those  of  modern  crown-work, 
though  most  important  in  their  results,  is  not  so  marked  as  regards 
constructive  details. 

Richmond  Porcelain  and  Gold  Collar  Crown. — The  gold  collar 
crown  wTith  porcelain  front  of  present  use  is  practically  the  gold- 
backed  pivot  tooth  of  former  years,  with  the  addition  of  a  collar 
to  inclose  the  end  of  the  root.  This  addition  of  a  collar,  though 
apparently  simple  to  conceive,  was  slow  of  development.  It  was 
not  until  such  a  form  was  presented  and  its  advantages  demon- 


Root   Prepared 
for  Pivot. 


Fig. 


ARTIFICIAL  CROWN -WORK.  47 

strated  by  Dr.  C.  M.  Richmond,  about  1878,  that  its  true  value 
and  possibilities  were  appreciated,  more  especially  respecting  the 
support  it  was  capable  of  affording  in  bridge-work  operations. 

The  Earlier  Operations. — The  earlier  operations  in  porcelain 
crown-work  were  almost  entirely  confined  to  the  incisor  and  cuspid 
teeth,  the  object  being  restoration  for  appearance  rather  than 
utility.  We  find,  though,  on  investigating  the  history  of  the  art, 
that  some  effort  was  also  made  by  a  few  of  the  earlier  practi- 
tioners to  maintain  and  restore  the  usefulness  of  affected  back 
teeth  with  crown- work.  Prominent  among  these  was  J.  Paterson 
Clark,  a  dental  practitioner  in  London,  England,  who,  as  early  as 
1836,  published  a  description  of  his  method  of  restoring  decayed 
and  abraded  molars  to  usefulness  by  covering  them  with  gold 
caps  stamped  up  on  a  metal  die  of  the  tooth. 

Fig.  44. 


The  Morrison  and  Beers  Gold  Crowns. — Similar  operations 
were  described  and  practiced  later  on  in  this  country  by  Dr.  W.  1ST. 
Morrison,  in  1869,  and  were  brought  into  more  prominence  by 
Dr.  J.  B.  Beers,  who,  in  1873,  secured  a  patent  for  his  method  of 
capping  teeth  with  gold,  as  illustrated  in  Fig.  41. 

During  the  progressive  modifications  in  crown-work  which 
evolved  from  the  gold-pivot  tooth  or  crown  to  the  gold-collar  porce- 
lain crown  of  the  present  time,  many  improvements  on  the  original 
porcelain  pivot  tooth  as  a  ready-made  crown  were  developed  and 
introduced  into  practice.  One  of  the  first  of  this  character  to 
attain  prominence  was  the  Poster  crown. 

The  Foster  and  Lawrence  Crowns. — The  Foster  crown,  intro- 
duced by  Dr.  E.  W.  Foster,  in  1855,  and  so  named,  although 
similar  to  one  patented  by  Dr.  H.  Lawrence,  in  1819,  differed 
from  the  commonly  used  pivot  tooth  in  having  a  perforation  in 
the  center  of  the  palatal  side  on  a  line  with  the  root-canal.     The 


48 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


orifice  was  shaped  to  accommodate  the  head  of  a  screw  (Figs.  45 
and  46)  by  which  the  crown  was  attached  to  the  root.  The  object 
of  this  form  was  to  dispense  with  the  use  of  wood  as  a  pivot  or 
post. 

The  Mack  and  Howland=Perry  Crowns. — The  first  form  of 
porcelain  crown  introduced  which  protected  the  end  of  the  root 
by  the  use  of  cement  for  its  attachment  was  devised  by  Dr.  C.  II. 


Fig.  45. 


Fig.  46. 


Mack,  in  1S72.  It  consisted  of  a  hollow  porcelain  crown,  with  a 
cavity  in  the  base  of  a  shape  and  size  to  admit  the  extremities  of 
pins  screwed  into  the  root  or  cemented  in  the  canal.  The  crown 
was  cemented  on  the  root  over  these  pins  with  gutta-percha,  amal- 
gam, or  zinc  oxychlorid.  The  Mack  crown  proved  unreliable 
in  practical  use  because  of  the  insecurity  of  the  attachment.  The 
Howland  and  Perry  crowns,  which  were  so  nearly  identical  that 
they  became  known  as  the  Howland-Perry  crown  (Figs.  47,  48), 


Fig.  47. 


Fig.  48. 


improved  on  the  Mack  by  imparting  to  the  cavity  in  the  base  a 
better  form  for  the  retention  of  the  screws  in  the  cement  and  a 
more  suitable  curve  to  the  base. 

The  Gates=Bon\vill  Crowns — The  next  noticeable  improve- 
ment in  all-porcelain  crowns  appeared  in  the  Gates  and  Bonwill 
crowns,  the  former  being  the  invention  of  Dr.  W.  H.  Gates,  about 
1875,  and  the  latter  of  ""Dr.  W.  G.  A.  Bonwill,  in  1881.     These 


ARTIFICIAL  CROWN-WORK. 


49 


also  were  so  nearly  alike  that  they  were  called  "Gates-Bonwill" 
(Figs.  49  and  50).  One  of  the  advantages  this  crown  possessed 
over  the  Foster  was,  that  amalgam  was  used  for  its  attachment, 
protecting  the  end  of  the  root  from  decay.    The  base  of  the  crown 


Fig.  49. 


Fig.  50 


was  concave  and  the  aperture  for  the  post  of  a  triangular  form. 
The  crown  was  secured  to  the  root  with  a  screw-post,  or  a  flat  pin 
with  tapering  ends,  anchored  with  the  amalgam  that  attached  the 
crown.    This  crown  was  extensively  used  for  several  years. 

The  How  Crown. — The  How  crown  (Figs.  51,  52)  was  in- 
vented by  Dr.  W.  S.  How,  in  1883.  Its  novel  feature  was  the 
formation  of  a  sufficient  concavity  in  the  palatal  side  of  the  in- 


Fig.  51. 


Fig.  52. 


cisors  and  cuspids  to  afford  space  for  four  pins  in  the  porcelain 
with  room  between  them  for  the  adjustment  of  the  screw-post. 
The  crown  when  fitted  was  attached  by  bending  the  pins  around 
the  post  and  packing  around  them  and  filling  the  cavity  of  the 
crown  with  amalgam. 

The  Weston  Crown. — The  Weston  crown,  introduced  by  Dr. 
Henry  Weston  about  the  same  time,  was  similar  in  principle  and 
structure,  with  this  difference:  The  Weston  post  was  flat  and 
riveted  to  the  crown  before  insertion.  The  post  was  first  cemented 
in  position  with  a  small  quantity  of  zinc  oxyphosphate,  and  the 


50 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


remainder  of  the  space  then  filled  with  either  gold  or  amalgam. 
Fig.  53  shows  the  various  steps  in  the  operation. 

Another  form  of  modern  introduction,  but  limited  use,  was  the 


Brown  crown,  illustrated  in  Fig.  54.  It  was  made  with  a  conical 
base  and  with  a  long  pin  baked  in  the  porcelain.  In  mounting  it, 
the  end  of  the  root  was  concaved  to  receive  the  convex  porcelain 
base.     The  object  of  this  form  of  construction  was  to  permit  the 


Fig.  54. 


Fig.  55. 


porcelain  to  be  removed  in  a  close  bite  without  materially  weaken- 
ing the  crown. 

The  New  Richmond  Porcelain  Crown — In  the  New  Rich- 
mond porcelain  crown,  illustrated  in  Fig.  55,  which 
was  also  of  the  all-porcelain  variety,  a  cavity  was 
provided  at  the  base  to  exert  some  degree  of  lateral 
pressure  on  the  root  and  thus  help  to  guard  against 
its  fracture. 

The  development  of  what  were  classed  as  ready- 
made  porcelain  crowns  as  here  traced,  brings  us  to  the  forms  which 
are  now  in  use  and  which  will  be  described  in  the  succeeding 
chapter. 

Advantages  Conferred  by  Improvements  in  Cements. — 
Doubtless  much  of  the  present  perfection  of  methods  by  which 
the  effective  results  now  achieved  in  this  branch  of  dental  pros- 


ARTIFICIAL  CROWN-WORE.  51 

thesis  are  made  possible,  is  due  to  the  use  of  cemeuts  with  which 
the  ends  of  roots  and  crowns  are  hermetically  inclosed.  Of  these 
the  first  was  zinc  oxychlorid,  introduced  about  1860,  though  not 
used  in  this  work  till  some  years  later.  More  important  was  zinc 
phosphate,  first  made  known  about  1877,  while  a  better  under- 
standing of  the  properties  of  gutta-percha  as  applied  to  this  pur- 
pose has  contributed  not  a  little  to  the  result. 

Classification  of  Modern  Cro\vn=Work. — Modern  artificial 
crown-work  affords  extensive  facilities  for  restoring  the  crowns  of 
natural  teeth,  and  furnishes  means  of  support  for  bridge-work. 

The  consideration  of  modern  artificial  crown-work  as  presented 
in  succeeding  chapters  is  divided  into  two  general  systems, — the 
porcelain  and  the  gold.  Under  the  porcelain  system  are  included 
ready-made  porcelain  crowns,  applied  with  or  without  collars;  and 
under  the  gold  system,  all-gold  crowns,  gold  crowns  with  porcelain 
fronts,  and  special  operations. 


CHAPTER    II. 

Principles  Involved  in  Crown-Work. 

nomenclature  of  crown-work — the  object  of  crowning  opera- 
tions— the  subject  of  occlusion— malformed  occlusal  sur- 
faces— the  post  in  relation  to  the  canals  and  roots — the 
post  in  relation  to  post  or  dowel  crowns — short  and 
long  crowns — principles  governing  the  construction  of 
root-caps  without  collars— posts  in  relation  to  collar 
crowns— selection  of  porcelain  teeth— dependence  of 
crown-work  operations  on  asepsis. 


To  systematize  and  explain  the  nomenclature  used  in  the  de- 
scriptive details  of  crown-work,  the  following  definitions  of  terms 
used  are  given : 

Fig.  56. 

l 


13  13 


29 


PRINCIPLES  INVOLVED  IN  CROWN-WORK. 


53 


9. 
10. 
11. 
12. 

13. 
14. 
15. 
if,. 
17. 


Apex. 

Cervix. 

Cervico-palatal  surface. 

Cervico-labial   surface. 

Labial  surface. 

Palatal  surface. 

Incisal  end. 

Occluding,    occlusal,    or    grinding 

surface. 
Palatal  cusp. 
Labial  or  buccal  cusp. 
Sulcus. 
Root-canal. 

Surface  of  end  of  root. 
Labial   or  buccal   section   of   end. 
Palatal  section  of  end. 
Post,  dowel,  pin,  or  pivot. 
Point  of  post. 


18.  End  of  post. 

19.  Cap   or   plate.      (This   part   when 

used  in  connection  with  a  collar 
is  more  generally  termed  the 
top  or  plate.) 

20.  Slot    between    cap    and    base    of 

porcelain  front. 

21.  Back  of   porcelain  front. 

22.  Metallic  backing. 

23.  Metallic   backing   on    incisal    sur- 

face. 

24.  Post,  dowel,  pin,  or  pivot. 

25.  Base  of  crown. 

26.  Collar. 

27.  Cervical  edge  of  collar  or  crown. 

28.  Occluding  edge  of  collar. 

29.  Cap  or  occluding  or  grinding  sur- 

face. 


Principles  Involved  in  Crown=Work. — The  practice  of  modern 
crown-work  consists  in  the  artificial  replacement  of  the  coronal 
portions  of  natural  teeth  affected  by  or  lost  from  caries,  for  the 
purpose  of  securing  a  better  appearance  or  greater  utility  or  both. 
In  bridge-work  operations  it  includes  also  the  capping  of  natural 
teeth  with  gold  and  the  artificial  restoration  of  excised  natural 
crowns  to  be  used  as  supports. 

No  matter  what  the  forms  in  which  teeth  and  roots  are  pre- 
sented for  crown-work,  invariable  mechanical  principles  govern  the 
application,  though  the  style  or  method  of  construction  admits  of 
selection.  The  general  condition  of  the  roots  or  teeth  to  be  operated 
on,  and  the  character,  direction,  and  force  of  the  occlusion  are 
subjects  that  govern  the  application.  The  location  in  the  mouth 
and  the  object  of  the  operation  indicate  the  preferable  style  or 
method  of  construction.  Operations  on  the  six  front  teeth  will 
generally  be  influenced  by  appearance,  and  those  on  the  back 
teeth  principally  by  utility. 

The  Object  of  Crowning  Operations — In  the  crowning  of 
roots  and  pulpless  teeth  having  the  coronal  section  practically  de- 
stroyed by  decay,  protection  against  its  recurrence  and  the  fracture 
of  the  root  are  the  subjects  to  be  specially  considered.  In  cases 
where  sound  teeth,  or  teeth  with  or  without  living  pulps,  only 
slightly  decayed,  are  to  be  capped  with  gold  as  supports  for  bridges, 
the  work  is  to  be  conducted  principally  with  the  view  of  preserva- 
tion of  the  coronal  section. 

Modifying  the  Occlusion — In  a  normal  state  of  the  occlusion 
of  the  teeth  the  force  of  mastication  is  received  in  an  upward  out- 


54 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 


ward  direction  on  the  palatal  and  incisal  surfaces  of  the  six  upper 
front  teeth  and  inwardly  in  an  opposite  direction  on  the  incisal  and 
labial  surfaces  of  the  corresponding  lower  teeth.  When  bicuspids 
and  molars  are  evenly  occluded  the  force  is  direct.  In  a  side  or 
lateral  motion  of  the  jaw  the  force  is  delivered  in  corresponding 
directions  against  the  occluding  surfaces  of  the  cusps.  This  lateral 
force  upon  the  cusps  in  mastication  is  proportionately  greater  when 
the  cusps  are  long  as  in  Fig.  57,  and  it  can  be  modified  by  giving 
them  the  entirely  practical  but  shorter  form  with  shallow  sulci, 
illustrated  in  Fig.  58.     This  result  can  usually  be  accomplished 


Fig.  57. 


Fig.  58. 


Fig.  59. 


Fig.  60. 


without  injuriously  affecting  the  appearance,  and  the  work  can  be 
materially  simplified  by  a  proportionate  reduction  of  the  cusps  of 
the  natural  antagonizing  teeth. 

As  the  cusps  of  the  bicuspids  and  molars  retain  them  in  proper 
alignment  with  their  antagonizing  teeth,  they  should  always  be 
formed  to  accord  with  an  outline  of  the  original  shape  of  the 
natural  teeth. 

Malformed  Occluding  Surfaces — Fig.  59  shows  an  upper  bi- 
cuspid crown  with  a  malformed  occluding  surface  of  a  shape  often 
improperly  given  in  a  case  of  close  occlusion. 

The  resultant  conditions  in  time  are  that  the  crown  and  root, 
because  of  the  gliding  pressure  exerted  on  the  surface  of  the 
crown,  are  pressed  outward  so  that  its  stability  and  usefulness  are 
gradually  impaired  and  finally  destroyed.  In  a  case  where  the 
symmetry  and  appearance  imperatively  demand  such  an  extension 
of  the  labial  cusps,  the  displacement  just  referred  to  will  be  pre- 
vented by  giving  sufficient  length  to  the  palatal  cusp  to  lock  the 


PRINCIPLES  INVOLVED  IN  CROWN-WORK. 


55 


crown  in  the  act  of  occlusion,  as  shown  in  Fig.  60.  This  principle 
may  be  advantageously  applied  in  construction  of  crowns  for  the 
six  front  teeth,  especially  the  cuspids,  when,  owing  to  the  loss  of 
the  back  teeth,  they  have  to  bear  the  force  of  occlusion.  A  slight 
shoulder  or  partial  cusp  will  materially  lessen  the  effect  of  the 
outward  gliding  pressure.     (See  Fig.  70.) 


Fig.  61. 


Fig.  62. 


Adjustment  of  Incisors  and  Cuspids. — In  the  adjustment 
of  incisor  and  cuspid  artificial  crowns  or  teeth  the  operator  should 
be  guided  by  the  fact  that  the  center  of  the  line  of  the  incisal 
surfaces  is  always  located  in  the  median  line  of  the  combined 
natural  crown  and  root,  as  is  shown  in  Figs.  61,  62,  and  63. 

Posts  in   Relation  to  the  Canals  and   Roots The  original 

forms  of  the  canals  and  roots- of  the  teeth  should  be  studied  and 
kept  well  in  mind  in  reaming  the  canals  for  the  reception  of  posts. 


Fig.  63. 


Fig.  64. 


The  pulp-canal  is  located  in  the  central  section  of  each  root,  in 
the  incisors  and  cuspids  very  nearly  on  a  straight  line  between 
the  end  of  the  root  and  the  center  of  the  incisal  edge  or  cusp.  (See 
Figs.  61,  62,  63,  64,  65.)  This  fact  will  materially  aid  in  deter- 
mining the  direction  or  angle  at  which  a  drill,  bur,  or  reamer 
should  be  introduced  into  these  teeth.    The  same  principle  may  be 


56 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


considered  in  the  conduct  of  operations  on  upper  bicuspids,  lower 
first  bicuspids,  the  buccal  roots  of  upper  first  and  second  molars, 
and  the  mesial  roots  of  lower  molars,  making  due  allowance  for 
such  curve  of  the  root  as  may  exist,  should  the  instrument  bo 
introduced  deeply  into  the  canal  (Figs.  66,  67,  68,  and  69).  When 
the  natural  crown  of  a  root  in  normal  alignment  with  the  other 


Fig.  66. 


teeth  has  been  nearly  or  entirely  lost,  the  angle  to  give  the  instru- 
ment may  be  calculated  by  the  adjoining  teeth. 

The  reaming  should  be  so  conducted  that  while  the  necessary 
enlargement  is  effected,  the  root  is  weakened  the  least  possible. 

Strength  is  most  required  on  the  approximal  sides  of  the  upper 
and  lowrer  six  front  roots,  as  the  pressure  imparted  by  the  post  in 
the  canal  is  almost  entirely  received  in  either  an  inward  or  out- 

Fig.  67. 


ward  direction.  Proper  reaming  of  the  canal  in  accordance  with 
its  original  shape  and  that  of  the  cervical  section  of  the  root,  and 
the  forming  of  the  post  to  correspond,  will  provide  the  greatest 
proportionate  amount  of  strength  for  both  root  and  post. 

As  the  most  strength  in  a  post  is  developed  in  the  line  of  its 
greater  diameter,  a  properly  adjusted  post  that  inclines  to  an  oval 
form  will  afford  greater  strength  than  a  round  one  composed  of 


PRINCIPLES  INVOLVED  IN  CROWN-WORK. 


57 


the  same  amount  of  the  metal.     (Fig.  71  outlines  a  cuspid  root 
and  oval-shaped  post.) 

Tapering  the  post  allows  it  to  be  introduced  deeper  into  the 
canal  without  excessive  reaming  than  if  made  of  a  uniform 
diameter  or  only  rounded  at  the  point.  The  point  of  the  post,  what- 


Fig.  68. 


Fig.  70. 


Fig.  71. 


Fig.  69. 


ever  the  shape,  should  be  immovably  fitted  or  anchored  in  the 
canal,  especially  when  the  remaining  portion  fits  loosely,  as  seen 
in  Fig.  72. 


Fig.  72. 


Fig.  73. 


Fig.  74. 


Fig.  75. 


Anchoring  the  point  defines  its  position  and  lessens  the  liability 
of  fracturing  the  root  under  pressure. 

AY  hen  the  point  of  a  post  is  not  anchored,  as  shown  in  Fig.  73, 
and  cemented  with  gutta-percha,  crown  and  post  are  likely  to  tilt 
under  continued  application  of  pressure,  as  seen  in  Fig.  74.     A 


58  CKOWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

weak  or  thin  post  is  liable  to  bend,  as  illustrated  in  Fig.  75.  Each 
of  these  conditions  causes  fracture  of  roots  carrying  post  or  dowel 
crowns,  or  of  crowns  with  very  small  or  improperly  applied  posts 
and  partial  collars. 

The  Post  in  Relation  to  Post  or  Dowel  Crowns — A  post  or 
dowel  crown  without  a  collar  is  dependent  entirely  on  the  post  or 
dowel  for  attachment  and  support.  In  this  function  the  post 
exerts  and  resists  in  its  incasement  and  foundation — the  root — all 
the  lateral  and  direct  pressure  incident  to  mastication.  The 
length,  shape,  and  size  of  a  post  should  therefore  be  regulated 
accordingly.  A  post  in  a  root  distributes  applied  pressure  its 
entire  length  along  the  walls  of  the  canal;  consequently,  in  the 


Fig.  70. 


Fig.  77. 


Fig. 


use  of  a  long  post,  a  proportionately  greater  area  is  involved  than 
with  a  short  one. 

Short  and  Long  Crowns — The  greater  the  distance  from  the 
end  of  the  root  the  force  is  exerted,  the  greater  the  proportion  of 
lateral  strain  the  walls  are  subjected  to.  Therefore  the  shorter 
the  crown,  the  less  is  the  leverage  or  pressure.  This  principle  is 
made  clear  by  Fig.  76.  The  incisal  edge  of  the  crown,  which  ends 
at  A,  will  not  exert  through  the  post  so  great  a  proportion  of 
pressure  on  the  root  in  mastication  as  one  with  an  incisal  edge  at 
B,  which  again  would  exert  less  pressure  than  one  extended  to  C. 
The  latter  would  especially  suggest  the  use  of  a  long  post. 

When  the  occlusion  of  the  six  front  teeth  is  deep  and  close,  as 
shown  in  Fig.  77, — a  condition  termed  "close  bite,'5 — the  crown 


PRINCIPLES  INVOLVED  IN  CROWN-WORK.  59 

and  teeth  or  crowns  as  they  occlude  exert  an  increasing  gliding 
pressure.  An  occlusion  of  this  character  always  demands  the 
longest  possible  close-fitting  canal  post.  In  occlusions  occurring 
nearer  the  incisal  surface,  termed  "open  bite,"  as  seen  in  Fig.  78, 
the  pressure  is  more  direct  and  proportionately  less  lateral  in  char- 
acter. 

Principle  Governing  the  Construction  of  Root=Caps  without 
Collars. — A  cap  or  plate  without  a  collar,  fitted  to  a  flat  or  slightly 
curved  end  of  a  root,  does  not  afford  a  positive  resistance  to  lateral 
pressure  in  supporting  a  crown.  This  resistance,  however,  can  be 
quite  effectually  accomplished  by  giving  a  deep  curve  to  the  sur- 
face of  the  end  of  the  root  at  the  labial  or  palatal  side,  or  both 
sides  combined, — as  resistance  requirements  suggest, — which  will 
be  proportioned  to  the  length  of  the  post.  The  edge  of  the  curve 
at  the  gum-margin  must  come  within  the  line  of  the  segment  of 
a  larger  circle  which  passes  over  the  center  of  the  surface  of  the 
end  of  the  root,  described  by  the  point  of  the  post  as  its  center; 
or,  in  other  words,  the  radius  or  distance 
from  the  point  of  the  post  to  the  extreme 
edge  of  the  curved  surface  of  the  side  of  the 
end  of  the  root  must  be  shorter  than  from 
the  point  of  the  post  to  the  center  of  the  line 
of  the  orifice  of  the  canal.  The  shorter  the 
post,  the  deeper  the  labial  and  lingual  edges 
of  the  curve  should  extend.  The  principle 
is  demonstrated  in  Tig.  79.  C  is  the  center 
of  the  root-end,  D  a  long  post,  and  E  a  short 
one.  AA  is  a  segment  of  a  circle  described  from  the  point  of  post 
E,  and  BB  a  similar  segment  described  from  D.  The  beveling  or 
curving  of  the  root  should  be  extended  beyond  AA  for  a  post  like 
E,  and  beyond  BB  for  post  D. 

Posts  in  Relation  to  Collar  Crowns. — In  collar  crowns,  as  the 
root  is  encompassed  by  the  collar,  the  principal  use  of  the  post  is 
to  retain  the  crown.  The  actual  length  and  size  of  post  required 
for  a  collar  crown  is  dependent  on  the  conditions  presented.  Deep, 
substantially  fitted  collars  require  the  aid  of  only  a  moderate  post. 
Xarrow  or  partial  collars  when  applied  to  the  six  front  teeth 
require  proportionately  larger  posts  for  the  crowns,  approximating 
in  size  to  those  used  for  the  ordinary  post  or  dowel  crown. 

The  force  of  occlusion  being  distributed  over  the  entire  occlud- 
6 


gQ  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

ing  surface  of  bicuspids  and  molars,  when  a  collar  is  applied  it 
should  entirely  encircle  the  root.  Crowns  on  these  roots  are 
therefore  not  so  dependent  for  security  on  posts  as  those  placed  on 
the  six  front  teeth.  A  substantial  properly  fitted  and  cemented 
post  in  any  root-canal,  whether  or  not  attached  to  the  artificial 
crown,  always  materially  strengthens  the  root. 

Selection  of  Artificial  Teeth.- — Crown-work  is  a  branch  of 
dental  prosthesis  which  requires  judgment  and  skill  in  the  selec- 
tion of  porcelain  teeth  for  the  work  in  hand,  as  one  of  the  great 
objects  in  dental  art  should  be  to  conceal  art.  In  a  large  propor- 
tion of  operations  on  the  front  teeth,  the  result  has  to  be  studied 
more  with  reference  to  appearance  than  utility.  In  size,  form,  and 
shade,  porcelain  teeth  selected  for  one  side  of  the  mouth  should 
match  the  corresponding  tooth  or  teeth  on  the  other  side.  The 
shade  should  be  fully  as  dark,  never  lighter.  Uniformity  in  shade 
of  the  different  teeth  should  be  avoided.  Central  incisors  usually 
require  to  be  the  lightest  in  shade,  laterals  slightly  darker,  the  cus- 
pids darker  than  the  laterals,  and  the  bicuspids  about  the  shade  of 
the  laterals.  The  shades  of  the  lower  teeth  vary  in  the  same  order, 
but  are  a  little  darker.  Observation  of  this  rule  in  selection  will 
avoid  that  extreme  sameness  of  shade  so  frequently  characteristic 
of  artificial  teeth,  and  cause  them  to  more  closely  approach  natural 
teeth  in  appearance. 

The  proper  and  successful  performance  of  crown-work  opera- 
tions depends  largely  upon  the  due  observance  of  the  principles 
here  presented. 

Dependence    of    Crown=Work    Operations    on    Asepsis 

Crown-work  in  the  restoration  of  badly  decayed  pulpless  teeth  or 
roots  is  intimately  associated  with  their  treatment,  more  especially 
as  regards  the  establishment  and  future  maintenance  of  a  state  of 
asepsis.  The  usefulness  of  operations  depends  on  the  successful 
assurance  of  this  condition.  Recent  investigations  show  conclu- 
sively that  ordinarily  infection  of  pulpless  teeth  and  roots  occurs 
from  the  oral  cavity.  It  is  therefore  clear  that  root -canal  filling 
and  such  restoration  of  any  portion  cf  the  natural  crown  present 
as  may  be  required  preparatory  to  capping  should  be  so  con- 
ducted as  to  offer  the  greatest  possible  obstruction  to  infection. 


CHAPTER    III. 

The  Porcelain  Ready-Made  Crown  System. 

method  of  preparation  of  the  root— screw-posts— use  of 
plaster  model  for  fitting  crowns— the  logan  crown— the 
fellowship  crown  and  the  brewster  crown— the  davis 
crown — ash's  tube  teeth  and  crowns. 

The  porcelain  ready-made  crowns  in  use  at  the  present  time 
are  the  results  of  progressive  development  of  this  branch  of  the 
art  from  what  was  originally  styled  the  porcelain  "pivot-tooth.'' 

Porcelain  ready-made  crowns  are  used  by  many  dentists  almost 
exclusively,  excepting  only  the  occasional  insertion  of  a  gold 
cap-crown  on.  a  posterior  tooth.  The  reasons  for  this  are  the 
greater  intricacy  of  the  construction  of  gold  crowns  and  personal 
objections  to  crowns  with  bands  or  collars. 

The  advocates  of  the  porcelain  ready-made  crown  claim  for 
it  natural  appearance,  restoration  of  contour,  strength,  and  cleanli- 
ness, together  with  simplicity  of  construction  and  easy  adaptation 
and  attachment  to  the  root,  to  which  the  crown  is  hermetically 
sealed.  Porcelain  ready-made  crowns  at  present  in  use  are  made 
in  two  general  styles.  In  one  the  end  of  the  pivot,  post,  pin,  or 
dowel,  as  it  is  variously  termed,  is  baked  in  the  porcelain  when 
the  crown  is  made,  and  the  other  end  cemented  into  the  root 
when  the  crown  is  adjusted.  The  Logan,  Fellowship,  and  Brew- 
ster crowns  are  of  this  class.  In  the  other  style  the  crown  is 
attached  to  the  root  by  a  pivot,  post,  or  screw,  one  end  of  which  is 
cemented  in  the  root  and  the  other  in  the  crown,  such  as  the 
Davis  and  Ash. 

Special  advantages  are  claimed  for  each  of  these  several  forms 
of  crowns.  A  general  knowledge  of  the  different  styles  is  there- 
fore essential  to  determine  the  adaptation  of  each  to  the  require- 
ments of  a  case. 

Crowns  in  which  the  post  is  to  be  cemented  admit  of  alignment 
with  the  other  teeth,  in  some  cases  more  easily  than  those  which 
are  made  with  the  post  in  position.     The  attachment  of  the  crown 

01 


62  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 

to  the  post,  however,  is  not  nearly  as  reliable  when  cemented  as 
when  baked  in  the  porcelain,  especially  in  close  "bites." 

Preparation  of  the  Root=End — The  preparation  of  the  end  of 
the  root  and  canals  to  receive  and  retain  posts  is  about  the  same 
for  all  of  the  different  styles  of  ready-made  porcelain  crowns. 
The  end  of  the  root  is  trimmed  to  the  gum-margin  in  the  front 
teeth,  slightly  below  it  at  the  labial  side,  to  hide  the  intended 
union  of  porcelain  with  root.  This  may  require  the  removal  of 
the  enamel  at  the  cervico-labial  section,  but  not  around  the  entire 
periphery  of  the  root.  The  length  of  the  root-canal  is  measured 
with  a  root-canal  plugger  and  its  flexible  gage.  A  disk  of  rubber- 
dam  can  be  placed  on  the  plugger  and  used  for  the  same  purpose. 
By  this  means  the  proper  length  for  the  post  is  determined.  The 
dimensions  of  the  root  determine  the  diameter.  Fill  that  part  of 
the  end  of  the  canal  which  will  not  be  occupied  by  the  post. 
Enlarge  the  canal  with  Gates-Glidden  drill  as  deep  as  required 
to  accommodate  the  post  for  the  crown  which  is  to  be  inserted. 
Xext,  with  a  gage-plate,  determine  the  size  of  the  post,  and  with 
small-sized  fissure-burs  gradually  ream  the  canal  to  a  dimen- 
sion which  the  post  will  fit  tightly.  A  post  to  be  inserted  in  a 
root  to  attach,  for  instance,  a  Davis  or  tube  crown,  is  preferably 
made  of  iridio-platinum  wire. 

Sere w= Posts. — A  size  is  selected  which  will  accurately  fit  the 
hole  in  the  porcelain  crown.  The  surface  of  the  wire  should  be 
roughened  either  by  cutting  a  fine  screw-thread  with  a  screw- 
plate  or  by  rolling  the  wire  under  a  flat  file.  The  canal  should 
be  reamed  to  accommodate  the  post.  The  point  of  the  post  beyond 
the  reamed  section  may  be  tapered  and  introduced  deep  into  the 
canal  for  security  and  to  strengthen  the  root  in  such  cases  as  sug- 
gest it.  The  post  is  cemented  in  the  root  with  zinc  oxychlorid 
or  oxyphosphate.  Of  the  two  the  oxyphosphate  is  the  more 
easily  manipulated  and  more  reliable  for  the  retention  of  the  post, 
but  otherwise  the  antiseptic  properties  of  the  oxychlorid  strongly 
recommend  it. 

A  screw-post  screwed  into  the  root  is  by  some  given  preference 
to  one  which  is  only  cemented,  and  in  very  short  roots  can  often 
be  used  to  advantage.  The  How  screw-posts  and  appliances, 
illustrated  in  Figs.  80  to  85,  are  generally  used  for  the  purpose 
in  the  following  manner: 

"1.     Set  gage  on  a  Gates  drill  (Fig.  80)  to  one-half  the  gaged 


THE  PORCELAIN  READY-MADE  CROWN  SYSTEM. 


63 


depth 


Fig. 

SO. 


of  the  canal,  or  further,  if  the  circumstances  require  it  and 
conditions  will  safely  permit,  and  drill  to  that  depth. 

"2.  Set  the  twist-drill  in  its  chuck  (Fig.  81)  to  project 
the  same  length  as  the  Gates  drill,  and  drill  the  root  to 
exactly  that  depth. 


Fig.  81.     Fig.  82.      Fig.  83. 


Fig.  84. 


Fig.  85. 


Fig.  87. 


"3.  Enlarge  the  mouth  of 
the  canal  one-sixteenth  of  an 
inch  deep  all  around  to  near  the 
margin  of  the  root,  as  shown  in 
Fig.  82,  using  square-end  fissure- 
bur  Xo.  59,  and  then  with  oval 
bur  Xo.  94,  undercut  a  groove 
lingually  and  at  the  sides. 

"4.  Set  the  tap  in  its  chuck  (Fig.  83)  a  trifle  less  in 
length  than  the  drill,  oil  it,  and  carefully  tap  the  root  to 
the  gaged  depth. 

"5.  Insert  the  post  (Fig.  84)  in  its  chuck  (Fig.  85)  to 
the  exact  gage  of  the  tap,  and  turn  the  thumb-screw  down 
hard  on  the  end  of  the  post,  then  screw  the  post  into  the 
root  by  hand,  release  the  thumb-screw,  unscrew  the  chuck 
a  half-turn,  bend  the  post  until  the  chuck  stands  in  center 
line  with  the  adjoining  teeth,  and  unscrew  the  chuck  from 
the  post." 

The  appearance  of  posts  in  relation  to  roots  is  illustrated 

in  Figs.  86  and  87. 

In  these  operations,  as  likeAvise  in  others,  posts  of  platinum  or 

iridio-platinum  are  to  be  preferred  to  those  made  of  alloys  that 

contain  a  large  percentage  of  the  baser  metals,  as  the  ultimate 

corrosion  of  the  latter  tends  to  impair  the  dentin. 


04  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Just  before  a  screw-post  is  screwed  into  the  canal,  it  is  advisable 
to  apply  a  little  of  a  thin  mixture  of  cement  on  its  surface. 

Plaster  Model  to  Fit  Crown — A  plaster  model  and  "bite"  of 

the  case  will  aid  in  the  selection  of  a  suitable  crown  and  in  the 
preliminary  fitting  to  the  root.  A  post  of  wood  or  metal  placed 
in  and  left  extending  from  the  root-canal,  and  then  withdrawn 
in  the  impression,  will  give  the  line  of  the  canal  in  the  plaster 
model.  Exposing  the  end  of  the  root,  by  pressing  the  gum  away 
FlG  8g  from  it  with  gutta-percha 

preliminary  to  the  opera- 
tion, will  greatly  assist  the 
operator,  by  enabling  him 
to  avoid  accidental  lacera- 
tion of  the  adjoining  mem- 
branes, and  the  annoyance 
attending  their  bleeding, 
besides  permitting  him  to 
carefully  study  the  adjust- 
ment and  cementation  of 
the  crown.  The  obtaining 
of  a  close  joint  is  much 
facilitated  in  all  forms  of 
porcelain  crowns  by  pass- 
ing a  disk  of  black  marking-  or  impression-paper  over  the  post  or 
pin  which  is  to  retain  the  crown,  and  placing  the  crown  in  position 
on  the  root.  (See  Fig.  88.)  Cut  the  paper  in  a  strip,  and,  to  admit 
the  post,  form  holes  with  a  punch,  as  shown  on  margin  of  Fig.  88. 
The  points  which  prevent  perfect  adjustment  are  marked  on  both 
root  and  crown,  either  of  which  can  be  dressed  off  accordingly  as 
seems  most  desirable. 

Crowns  in  which  the  post  is  baked  in  the  porcelain  will  first  be 
described. 

The  Logan  Crown. — The  Logan  crown,  now  so  extensively 
used,  was  invented  by  Dr.  ]VI.  L.  Logan.  Its  distinctive  features 
are  the  cupping  out  of  the  base  surrounding  the  strong  platinum 
post,  the  form  of  the  post,  and  the  baking  of  the  post  in  the  porce- 
lain. As  originally  made  the  post  was  round,  but  shortly  after 
the  tapered  I-beam  post  was  introduced.  At  first  the  I-beam  post 
was  plain  (Fig.  89),  and  it  was  nicked  or  serrated  across  the  flanges 
by  the  dentist  when  mounting  the  crown.     The  present  form,  with 


THE  I'ORCELAIX   READY-MADE  GROWN  SYSTEM. 


65 


a  continuous  double  flange  and  transverse  ribs,  is  shown  in  Figs. 
90,  91,  92,  93,  and  94.  The  larger  end  is  baked  in  the  porcelain, 
the  flanges  and  ribs  affording  a  very  strong  hold.  The  cupped-out 
base  permits  the  use  of  a  larger  body  of  cement  in  setting,  and 
the  ribs  give  the  cement  a  hold  similar  to  that  of  the  porcelain,  the 
whole  forming  an  ideally  secure  mounting. 


Fig.  89.         Fig.  00.   Fig.  01.     Fig.  02. 

n 


Fig.  93. 


Fig.  95. 


Original  form  of 
the  Logan  Crown. 

Fig.  96. 


Fig.  94. 


Fig.  97. 


Set  of  six  front  upper  crowns,  natural  size. 


The  cupping  out  of  the  base  also  gives  a  great  advantage  in 
fitting  the  crown,  as  the  comparatively  narrow  rim  is  ground  away 
with  but  little  labor  and  no  risk  of  marring  or  destroying  the  post 
in  the  process. 

Mounting. — In  the  preparation  of  a  root  for  a  Logan  crown 
the  root-canal  is  enlarged  and  so  shaped  that  the  post  if  possible, 
at  least  at  its  point,  shall  fit  tightly.  This  is  best  done  by  first  using 
the  Gates-Glidden  drill  and  then  enlarging  the  canal  to  the  proper 
form  and  size  with  a  root-canal  reamer  (Figs.  95  and  96). 


66 


CBOWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


The  root  surface  at  its  labial  side  is  preferably  trimmed  with 
suitably  shaped  corundum-points  or  wheels,  or  with  a  root-facer 


Fig.  98. 


Fig.  99. 


Fig.  100. 


Enlarged  sec- 
tional view  of 
a  left  central  in- 
cisor root  with 
anchor-post  in 
position. 


(Figs.  97  and  98),  so  as  to  give  it  a  labial  slope,  which  will  permit 
the  lapping  of  the  labial  face  of  the  crown  at  the  cervical  border 
over  the  face  of  the  root  and  effect  an  artistic  as  well  as  a  desirable 


Fig.    102. 


Fig.    103. 


form  of  joint  under  the  gum-margin.  As  the  root-canal  is  being 
reamed  the  post  of  the  crown  is  to  be  frequently  inserted  (Fig. 
99)  to  determine  the  fit  (Fig.  100)  and  proper  alignment  of  the 


THE  PORCELAIX  READY-MADE  CROWN  SYSTEM. 


67 


crown.  When  the  base  of  the  crown  touches  the  end  of  the  root, 
points  of  contact  that  interfere  with  an  accurate  adaptation  should 
be  removed.  This  can  be  effected  by  trimming  either  the  surface 
of  the  root  or  the  base  of  the  porcelain  crown. 

When  the  root  or  porcelain  requires  to  be  extensively  removed, 
it  is  generally  best  done  with  a  safe-side  wheel,  such  as  is  shown 
in  Figs.  101  and  102,  to  avoid  injury  to  adjoining  teeth  or  the 
post.  At  this  stage  of  the  fitting  the  use  of  a  disk  of  articulating 
paper  (Fig.  88),  as  already  explained,  will  simplify  and  facilitate 
the  operation.    Fig.  103  illustrates  a  properly  fitted  Logan  crown. 

For  short  or  small  roots  the  post  of  a  Logan  crown  should  be 
proportionately  reduced  in  length  or  size.  For  bifurcated  bicus- 
pid roots  the  post  can  be  bent  as  shown  in  Fig.  104.     Fig.  105 


Fig.   104. 


Fig.   105. 


Fig.  106. 


Fig.  107. 


illustrates  the  best  manner  of  bending  the  post.  A  preferable 
method  to  practice  in  some  cases,  that  of  splitting  the  post,  is  ex- 
hibited in  Figs.  106  and  107. 

Zinc  oxyphosphate  or  gutta-percha,  or  the  two  combined,  are 
used  to  cement  the  Logan  and  similar  styles  of  ready-made  porce- 
lain crowns. 


Method  of  Fitting  Logan  Crown  by  Model  of  Natural  Tooth. 

First  prepare  the  face  of  the  root  to  be  crowned  as  desired 
(A,  Fig.  108),  and  having  selected  a  suitable  crown,  B,  bend  the 
pin,  if  necessary,  so  as  to  make  a  proper  alignment. 

Next  place  a  piece  of  sheet  wax  around  the  pin  next  to 
the  porcelain.  C,  then  take  ISTo.   60  tin  foil  and  trim  a  disk  3 


68 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


little  larger  than  the  abutment,  D,  pierce  the  center  of  the 
disk  with  the  crown  pin  or  instrument  shown  in  the  margin,  E, 
pushing  the  disk  down  until  it  touches  the  wax;  place  the  crown 

on  the  root  and  force 
it  to  place,  F,  the  wax 
driving  the  tin-foil  disk 
to  a  perfect  apposition 
with  the  abutment  of 
the  root. 

Remove  the  crown 
with  the  wax,  holding 
the  tin-foil  disk  in  posi- 
tion, and  with  a  pair 
of  sharp-pointed  scissors 
snip  the  edges  of  the 
disk  slightly  all  around. 
Place  a  small  pellet  of 
wax  on  the  point  of  the 
pin,  H,  then  insert  the 
pin  up  to  the  porcelain 
in  quick-setting  plaster, 
I;  after  the  plaster  hard- 
ens warm  the  crown  and 
remove  it,  the  snipped 
edges  of  the  disk  serv- 
ing to  hold  it  in  position; 
clean  off  the  wax  and 
replace  the  crown  on  the 
model,  and  you  have  a 
perfect  metallic-surfaced 
model  of  the  abutment 
of  the  root  to  which  to 
grind  with  a  perfect 
view  of  every  surface  of 
the  root,  the  wax  which 
was  on  the  end  of  the  pin  allowing  it  to  penetrate  the  plaster 
as  the  porcelain  is  ground  away.  By  this  method  a  Logan  crown 
can  easily  be  made  to  fit  perfectly. 


THE  PORCELAIN  READY-MADE  CRO^Y^7  SYSTEM.  QQ 

The  Fellowship  Crown  and  the  Brewster  Crown. 

The  Fellowship  crown  (Fig.  109)  and  the  Brewster  crown 
(Fig.  110)  are  crowns  with  fixed  posts.  The  posts  are  made  of  a 
German  silver  alloy,  which,  after  the  crowns  have  been  baked,  are 
attached  by  another  baking  with  a  low-fusing  porcelain.    The  post 


Fig.  lOfl. 


Fig.  110. 


of  the  Fellowship  is  additionally  secured  by  a  piece  of  wire,  which 

passes  laterally  through  a  perforation  in  the  post  and  base  of  the 

crown.     The  application  of  these  crowns  is  very 
Fig.  ill.  .     ..  ..    ,    ^  ^     T 

similar  to  that  of  the  Logan  crown. 

The  Davis  Crown. 

This  form  of  crown  (Fig.  Ill)  has  a  cavity  ex- 
tending into  the  base  of  the  crown,  the  orifice  of 
which  is  reamed.  The  dowel-pin,  which  is  made 
of  German  silver,  has  a  shoulder  or  rim  near  the 
end.  The  end  of  the  pin  fits  in  the  cavity  of  the 
crown  and  the  rim  in  the  reamed  section.  When 
the  crown  and  dowel-pin  have  been  propefrly 
fitted  to  the  root,  if  oxyphosphate  is  the  cement  to 
be  used,  post  and  crown  may  be  cemented  in  position  simultane- 
ously. If  gutta-percha  is  preferred  for  the  root-canal,  the  dowel- 
pin  is  first  cemented  in  the  crown  with  oxyphosphate,  and  after 
it  has  set  the  pin  is  fixed  in  the  root  with  the  gutta-percha. 


70 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Ash's  Tube  Teeth  and  Crowns. 

These  teeth  have  a  perforation  through  the  center,  with  a  thin 
platinum  tube  baked  in  the  porcelain.     They  are  supported  on  the 

Fig.  112.  Fig.  113.  Fig.  114.     root  ^7  tne  ^ute^  Post>  shown  in  Fig. 

113.  When  the  crown  is  properly 
ground,  the  base  is  to  be  countersunk 
sufficiently  to  receive  the  shoulder  of 
the  pin.  The  pin  is  then  bent  so  as  to 
allow  the  crown  to  assume  its  proper 
position  on  the  root.  The  socket-han- 
dle instrument,  shown  in  Tig.  120,  is  the  most  suitable  for  this 
purpose.  The  attachment  of  the  crown  is  made  by  first  securing 
the  pin  in  the  crown  with  sulfur  or  soft  solder  and  then  cementing 
the  fluted  post  in  the  root-canal  with  either  gutta-percha  or  oxy- 

Fig.  115.      PhoSPhate- 

Tigs.  116,  117,  118,  119,  120,  and  121  illustrate  Ash's 

dowel  crowns. 

They  are  applied  in  a  manner  similar  to  the  Davis 

crown.    The  dowels  or  posts  are  made  of  what  is  termed 

"Dental  Alloy,"  and  are  strongest  at  the  part  to  bear  the 

greatest  strain,  the  portion  where  the  crown  joins  the  root. 


Fig.  116. 


Fig.  117. 


Fig.  118. 


Fig.  119. 


Fig.  120. 


Fig.   121. 


THE  PORCELAIN  READY-MADE  CROWX  SYSTEM.  fl 

Remarks  on  the  Use  of  Porcelain  Ready-Made  Crowns  and  Crowns 

without  Collars. 

Porcelain  ready-made  crowns  have  some  decided  advantages. 
They  are  especially  useful  in  many  cases  where  an  inexpensive  or 
easily  adjusted  crown  is  required,  or  where  some  pathological  con- 
dition limits  the  probable  durability  or  permanence  of  any  opera- 
tion. In  the  insertion  of  porcelain  crowns,  the  removal  of  the 
whole  or  a  part  of  the  natural  crown,  which  could  be  utilized  to 
some  extent  as  a  foundation  by  other  systems,  has  given  rise  to 
various  objections.  If  the  natural  crown  is  entirely  cut  away  the 
pin,  or  post,  upon  which  almost  the  entire  support  of  the  artificial 
crown  is  thrown,  exerts  great  leverage  in  the  root-canal  when  no 
band  or  brace  is  present  on  the  exterior  of  the  root  to  relieve  the 
strain.  With  the  whole  force  of  mastication  bearing  directly  upon 
these  pulpless  roots,  whose  disintegration  is  slowly  but  constantly 
progressing,  the  inevitable  result  can  well  be  conjectured.  Sooner 
or  later  they  are  fractured,  and  their  usefulness  as  a  foundation 
ended.  These  facts,  and  the  lack  of  strength  incident  to  some 
forms  of  construction,  are  the  principal  objections  urged  against 
porcelain  crowns  as  ordinarily  inserted. 

Crowns  in  which  the  post  is  cemented  in  the  porcelain  are  less 
suitable  for  close  bites  than  those  stvles  in  which  it  is  baked  in. 


CHAP  TEE    IV. 

Porcelain  Crowns  with  Vulcanite  Attachment — A  Temporary 

Crown. 


Fig.  122. 


Fig.  122  illustrates  a  porcelain  crown  with  vulcanite  attachment. 
The  prepared  root  extends  at  the  palatal  side  a  little  below  the 
gum  line  (A)  at  the  point  B.  A  plate  tooth 
(C)  is  ground  and  fitted  to  the  root.  An  iridio- 
platinum  post  is  then  fitted  to  the  root,  flattened 
slightly  and  bent  at  D,  and  riveted  to  the  tooth. 
The  proper  alignments  of  the  tooth  and  post  to 
the  root  are  then  obtained,  and  they  are  invested 
and  the  post  soldered  and  strengthened  at  the 
point  D.  The  backing  is  then  grooved  and 
notched  slightly,  wax  applied,  the  crown  ad- 
justed to  the  root,  and  the  wax  shaped  so  as  to 
form  a  foundation  and  overlapping  edge  at  the 
palatal  portion  (E),  and  also  extend  around  the 
post  up  the  canal.  The  crown  is  next  removed, 
invested  in  a  flask,  packed  with  rubber,  and 
vulcanized.  In  trimming  and  finishing,  the 
rubber  may  be  allowed  to  form  a  partial  band  or 
collar  around  the  palatal  portion  of  the  root,  where  it  will  not 
show.     It  is  then  cemented  on  to  the  root  with  oxyphosphate. 

A  Temporary  Crown. — Fit  in  the  root-canal  a  post  of  metal, 
preferably  made  of  German  silver  wire.  Let  the  post  extend 
out  of  the  canal  about  one-eighth  of  an  inch  and  roughen  the 
sides.  Perforate  a  disk  of  the  heaviest  pattern  tin  or  1/1000  plati- 
num foil  with  the  post,  and  fit  to  the  end  of  the  root.  Fit  a  suit- 
able two-pin  vulcanite  porcelain  tooth  to  the  disk.  Groove  out  the 
porcelain,  if  necessary,  to  fit  over  the  post.  "Wax  the  porcelain 
tooth  to  the  disk  and  post,  remove,  and  invest  in  plain  plaster  of 
Paris.  Remove  the  wax  with  boiling  water,  and  apply  a  little 
muriate  of  tin  to  the  end  of  the  post.  In  the  place  of  the  wax,  flow 
fusible  metal,  which  melts  at  not  less  than  200  degrees,  or  tin 
72 


PORCELAIN  CROWNS  WITH  VULCANITE  ATTACHMENT.  73 

solder,  if  gutta-percha  is  to  be  used  to  cement  the  crown,  and 
instantly  press  down  firmly  into  the  investment  with  a  napkin 
over  the  finger;  cool,  remove,  trim,  and  cement  on  the  root  with 
gutta-percha  that  softens  at  a  low  heat. 


CHAPTER    V. 
Gold  Collar  Crowns. 

construction  and  adaptation  of  collars— methods  of  measure- 
ment—fitting of  collars  to  root  or  crown— application  of 
a  local  anesthetic— collar  crowns  hygienically  con- 
SIDERED. 

This  style  of  gold  crown  includes  those  methods  which  consist 
in  banding,  capping,  and  hermetically  inclosing  with  gold  the 
end  or  the  neck  of  a  root,  with  or  without  any  portion  of  a  natural 
crown,  for  the  purpose  of  securing  stability  to  the  artificial  crown, 
preventing  fracture  of  the  root  and  decay  of  the  parts.  This 
method  possesses  much  practical  value  as  a  preserver  of  tooth- 
structure  and  restorer  of  usefulness  to  the  teeth,  and  affords  excel- 
lent supports  for  bridge-work. 

Collar  crowns,  the  use  of  which  has  become  quite  general,  have 
been  described  by  many  writers  in  the  past.  Dr.  William  H. 
Dwindle  relates  the  application  of  the  method  to  a  crown  with  a 
porcelain  front,1  and  Drs.  W.  1ST.  Morrison2  and  J.  B.  Beers3 
tell  of  it  in  the  construction  of  all-gold  cap-crowns,  showing  its 
use  fifty  or  more  years  ago.4 

Collar  crowns  of  which  the  part  that  essentially  constitutes  the 
cap  is  constructed  in  sections,  will  be  first  described. 

The  Construction  and  Adaptation  of  Collars. 

Careful  study  of  the  different  forms  of  crowns  and  roots,  and 
of  the  anatomical  structure  and  relationship  of  the  contiguous 
parts,  is  most  essential  for  the  perfection  of  construction  and  adap- 
tation required  in  collars,  bands,  or  ferrules,  as  they  are  variously 
designated. 

1  American  Journal  of  Dental  Science,  April,  1855. 

2  Missouri  Dental  Journal,  May,  1S69. 

3  Circular  to  dental  profession,   1873. 

4  J.  Patterson  Clark,  1836. 
74 


GOLD  COLLAR  CROWNS. 


75 


Fig.  123. 


Fig.  124. 


Fig.  125. 


Many  devices  and  methods  in  use  facilitate  this  operation,  but 
its  skilful  performance  can  only  be  attained  by  study  and  practice, 
as  is  proved  by  the  easy  and  perfect  manner  in  which  it  is  done 
by  experts  in  crown-  and  bridge-work,  who  use  no  appliances  but 
pliers  and  shears  guided  by  an  intuitive  per- 
ception of  the  requirements  of  each  case. 

The  collar  is  preferably  made  of  22-  to 
23-carat  gold  plate;  the  tendency  now  is  to 
use  a  softer  alloy  of  plate  than  formerly. 
Pure  gold  plate  lined  with  platinum  is  also 
used,  and  platinum1  plate  in  special  cases. 

Gold  plate  of  No.  28  to  No.  30,  or  gold 
and  platinum  about  No.  30,  U.  S.  standard 
gage,2  affords  the  requisite  strength,  to- 
gether with  easy  adaptation  to  the  form  of 
the  crown  or  root.  The  size  of  the  cer- 
vix of  the  root  or  dimension  of  the  natural 
crown  to  be  capped,  and  whether  it  is  to 
effect  only  restoration  of  the  crown  or  to 
also  give  support  to  bridge-work,  should 
govern  the  choice  of  the  gage  of  plate  to  be 
used.  Cuspids  and  molars  require  a  heavier 
plate  than  small  laterals  or  lower  incisors, 
and  in  all  forms  of  gold  caps  the  gage 
should  be  increased  when  they  are  to  sup- 
port bridge-work. 

The  natural  crown  or  root  having  pre- 
viously been  properly  prepared  (see  page 
34),  a  strip  of  the  metal  is  cut  of  the  length 
required,  and  generally  from  one-fourth  to 
one-half  of  an  inch  in  width  (Fig.  123). 
The  end  to  underlap  at  joint  is  beveled  with 
a  file  (A,  Fig.  124).    The  strip  is  then  bent 

1  The  use  of  platinum  plate.  No.  32  to  34  gage,  is  specially  recommended  to 
students,  as  collars  formed  of  this  metal  are  not  apt  to  be  melted  in  any  of  the 
soldering  processes.  If  very  thin  platinum  is  used,  pure  gold  can  be  flowed 
over  the  outer  surface  after  it  is  adapted  to  the  cervix,  to  stiffen  it.  A  little 
dampened  fine  marble-dust  or  whiting  should  be  placed  on  the  inner  surface 
of  the  collar  during  the  operation  to  prevent  intrusion  of  the  gold  on  that 
part.  This  method  is  excellent  when  a  small,  narrow  collar  is  required  for 
an  incisor  crown  which  is  difficult  to  adjust  to  the  form  of  the  root. 

2  U.  S.  standard  gage  is  the  gage  always  referred  to  in  this  book. 


C5 


7g  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

with  suitable  pliers  (Fig.  125)  to  the  average  form  (Fig.  126),  any 

special  deviation  from  such  average  being  noted  (Fig.  127),  and 

to  the  size  of  the  cervical  periphery  of  the  root  of  the  tooth  to  be 

crowned.   The  edge  toward 
Fig.  126.  ,  &    ,  , 

the     gum     may     also     be 

^  (j  f~")    ~  trimmed,  so  that  it  will  in 

(\_V>  kJJj  a  measure  approximate  in 

C  \_  7     )  shape  the  curve  of  the  rnar- 

/-~^>-'  ^^~^  Sm  °^ tue  Sum-    -ft  *s  tiien 

J^-O  *-— ""'  placed    on    the    root    and 

\^~2)         adapted  as  closely  as  possi- 
ble to  its  form,  with  the 
upper   edge   of   the   metal 
pressing  gently  under  the 
\"^  V^"^  /     free  edge  of  any  portion  of 

^__y  * -^      the  gum  it  may  meet.     It 

\"VV'  y^^  j    is  then  removed  and  cut  so 

^- — '  ^ as  to  allow  the  ends  to  lap 

over  slightly.  The  adapta- 
tion to  the  root  is  then 
continued,  during  which 
process  the  metal  should 
be  clamped  at  the  joint, 
heated,  and  chilled  in  water 
after  each  trial,  in  order  to 
-C      )  maintain   the   shape   given 

-0\  t0  ti-     At  the  last  adjust- 

ment to  the  root,  the  lap- 


over  is  marked  on  the 
metal  with  a  sharp-pointed 
instrument,    the    collar    is 

The  palatal  side  of  the  superior  molars,  in  many  removed,      and      the     edges 

cases,  is  of  the  large  oval  form  indicated  br the  outer  }  U      £ M         together 

line  to  the  form  of  the  first  molar.    The  small  spurs  o  _      J  o 

indicate  the  points  generally  found  the  most  suitable  flush    01*    a    little    over    the 

tomakethe.ioi..t.  mark    The  joint  ismade  by 

placing  in  the  seam  the  least  possible  quantity  of  solder,  or,  better 
still,  of  fluxed  solder  filings,  and  holding  the  collar  with  a  clamp 
in  a  blue  (Bunsen)  gas  flame  while  the  solder  is  fused.  Another 
method  frequently  adopted  is  to  grasp  the  seam  at  the  cervical 
side  of  the  collar  with  the  points  of  a  clamp  such  as  is  shown 


GOLD  COLLAR  CROWNS. 


i  i 


Fig.  127. 


in  Fig.  193,  or,  better,  with  soldering-pliers  (Fig. 

128),  or,  ordinary  solder-tweezers  held  in  a  vise 

(Fig.  129),  and  unite  the  seam  only  at  the  extreme 

outer  end  with  an  atom  of  solder  fused  with  a 

blowpipe.     The  points  of  the  clamp  or  tweezers 

prevent  the  solder  from  flowing  along  the  joint. 

The  cervical  side  of  the  collar  is  left  open  by  this  method  of 

procedure,  which  permits  the  collar  to  be  slightly  contracted,  if 

desired,  then  the  solder  can  be  flowed  across  the  collar.    The  collar 

is  next  slipped  over  the  point  of  a  small  anvil,  and  the  joint  tapped 

and  trimmed  level. 

Methods  of  Measurement. — The  root  is  encir- 
cled with  a  strip  of  thin  sheet  copper,  about  Xo.  31 
gage,  previously  annealed,  one-sixteenth  of  an  inch 
or  less  in  width,  and  the  copper  fitted  to  the  cervix. 


Fig.  129. 


crb 


Fig.  128. 


It  is  removed,  and  cut  so  there  will  be  a  slight  lap- 
over  of  the  ends  on  the  root,  then  again  fitted  to  the 
root,  and  the  position  of  the  lap-over  end  marked  on 
the  copper.  This  little  strip  of  copper,  which,  being 
soft  and  flexible,  can  be  most  accurately  fitted  to  the 
root  without  inconvenience  to  the  patient,  when  re- 
moved shows  the  exact  length  and  shape  to  cut  the 
gold  or  platinum  for  the  collar. 

The  copper  pattern  is  laid  upon  a  strip  of  the  metal 
from  which  the  collar  is  to  be  formed,  from  one- 
quarter  to  one-half  inch  in  width,  and  the  exact 
length  required  is  marked,  and  the  metal  is  then 
cut  a  trifle  longer  than  the  mark  indicates  (less  than 
one-sixteenth  of  an  inch),  to  allow  for  an  overlap  joint. 


It  is  then 


bent  and  the  ends  brought  together,  the  outer  end  placed  even  or 


7S  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 

flush  with  the  mark,  and  soldered  as  above  described.     The  collar 
is  next  bent  to  the  shape  of  the  root,  when  it  is  ready  to  be  ad- 


Fig.  131. 


Fig.  132. 


% 


justed.    This  method  is  simple  and  practical,  and  also  economical, 
as  it  accurately  defines  the  amount  of  plate  required. 

To  measure  with  a  wire:  Form  a  loop  of  copper  wire,  about  30 
gage,  by  twisting  the  ends  together  with  pliers.  Slip  the  loop 
over  the  tooth  or  root,  press  the  wire  down  under  the  gum-margin, 


Fig.  133. 


Fig.  134. 


Fig.  135. 


and  twist  the  ends  with  the  pliers  until 
the  loop  fits  tightly  at  every  point  (Figs. 
130  and  131).  Slip  off  the  loop,  cut  it 
in  the  center,  and  extend  the  ends  length- 
wise in  opposite  directions,  as  shown  in 
Fig.  132.  Then  lay  it  on  the  surface 
of  the  plate  of  which  the  collar  is  to  be 
constructed,  and  mark  the  length.  Cut 
the  metal  beyond  this  mark  sufficiently 
to  allow  for  an  overlap;  bevel  and  lap 
the  ends  to  the  mark  and  solder  them. 

A  dentimeter,  such  as  is  exhibited  in  Fig.  135,  greatly  facili- 
tates measurements  with  wire.  The  ends  of  the  wire  are  passed 
into  the  hole  in  the  face  of  the  head,  and  out  through  the 
openings  which  are  cut  into  it  from  two  sides.  The  loop  thus 
formed  is  adjusted  around  the  tooth  or  root,  the  end  of  the  den- 


GOLD  COLLAR  CROWNS.  79 

timeter  is  pressed  against  the  root  at  the  gum-margin,  the  loop 
pulled  tight,  and  the  ends  of  the  wires  wound  around  the  boss  on 
the  handle.  A  few  turns  of  the  dentimeter  twist  the  loop  tight, 
when  the  wires  can  be  unwound  from  the  boss,  the  dentimeter  laid 
aside,  and  the  loop  removed. 

"When  a  mandrel  is  used  in  forming  a  collar,  the  size  or  shape 
is  first  taken  with  a  wire.  The  wire  ring  is  then  carefully  removed, 
laid  on  a  piece  of  air-chamber  tin,  a  piece  of  flat  iron  put  over  it, 
and  with  a  blow  from  a  hammer  on  the  iron  the  wire  is  driven  into 
the  tin  (Fig.  133).  It  is  next  extricated  from  the  tin,  slipped 
on  a  mandrel  that  represents  the  form  of  the  root  to  be  crowned, 
and  pressed  down  gently  as  far  as  it  will  go  without  stretching  the 
wire  (A,  Fig.  134).  The  distance  from  the  end  of  the  mandrel 
to  the  wire  is  then  measured  and  marked  on  a  strip  of  paper,  and 


Fig.  136. 


Fig.  137. 


Fig.  138. 


the  wire  removed.     The 
gold  to  form  the  collar  is 
then  bent  and  shaped  on 
the   mandrel,   with   the 
edge  which  is  to  form 
the  cervical  portion  (B) 
placed  a  little  below  the 
line  of  the  wire  (A),  as 
shown  by  the  measure- 
ment previously  taken.    The  ends  of  the  gold  are  beveled,  slightly 
lapped,  and  the  edge  of  the  lap-over  marked  (C)  and  soldered. 
The  collar  is  then  shaped  to  the  form  given  by  the  wire  in  the  tin, 
after  which  it  is  ready  for  adjustment  in  the  mouth. 

Fitting  of  Collar  to  Root  or  Crown. — When  the  collar  has 
been  formed,  it  is  adjusted  on  the  root  and  pressed  or,  with  the  aid 
of  a  piece  of  wood  placed  across  its  outer  edges,  gently  tapped  up 


80 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


to  the  margin  of  the  gum.  A  line  parallel  with  the  margin  is 
marked  with  a  sharp-pointed  instrument  on  the  collar  (A,  Figs. 
136  and  137),  which  is  then  removed,  trimmed  to  this  mark,  read- 
justed, and  again  marked  (B),  and  the  process  continued  until  the 
collar  fits  proportionately  under  the  margin  of  the  gum. 

If  this  part  of  the  operation  is  skilfully  performed,  and  the 
collar  is  not  forced  into  the  investing  membrane  of  the  root,  very 
little  pain  will  be  caused  the  patient. 

If,  on  adjusting,  a  collar  is  found  a  trifle  too  small,  it  is  easily 
enlarged  by  tapping  with  a  riveting  hammer  on  an  anvil  (Fig.  138) 
at  the  edge-end  of  the  collar  marked  B,  Fig.  124.  By  this  means 
the  surplus  gold  at  this  point  can  be  thrown  into  the  collar  and 
its  circumference  proportionately  enlarged  without  altering  its 
gage.     If,  on  the  contrary,  the  collar  should  prove  to  be  too  large 

Fig.  139. 


in  circumference,  the  difficulty  can  be  remedied  by  slitting  the 
gold  nearly  but  not  entirely  across  the  side  opposite  the  joint,  bevel- 
ing and  lapping  the  edges  slightly,  soldering,  and  trimming.  The 
edge  is  then  burnished  to  the  periphery  of  the  root.  For  the  pur- 
pose of  fitting  collars  a  set  of  burnishers  should  be  used  especially 
formed  to  suit  the  different  positions  and  avoid  irritation  of  the 
margin  of  the  gum.  (See  Fig.  139.)  Finely  serrated  foot-shaped 
gold-foil  condensers  can  be  advantageously  used  to  flatten  an  edge 
or  a  stiff  or  angular  point  of  a  collar. 

Application  of  a  Local  Anesthetic. — The  application  of  a  local 
anesthetic,  such  as  cocain,  will  lessen  pain  attending  the  adaptation 
of  a  collar  under  the  gum-margin.  Cocain  is  very  effective  in  the 
form  of  a  saturated  solution  in  glycerin.  The  parts  should  be 
surrounded  with   a  napkin,   or  with   bibulous  paper,   and  dried. 


GOLD  COLLAR  CROWNS.  81 

Then  a  drop  of  the  solution  is  placed  on  a  slab,  and  a  little  at  a 
time  is  carried  on  the  edge  of  a  thin  burnisher  and  applied  well 
up  under  and  around  the  free  margin  of  the  gum  of  the  tooth 
operated  on.  When  this  has  been  done,  some  of  the  excess  of  the 
solution,  which  will  usually  be  found  at  the  cervix,  may  be  rubbed 
on  the  labial  and  palatal  sides  of  the  gum.  The  patient  should 
be  directed  not  to  swallow  the  saliva  during  and  for  some  time 
after  the  application  of  the  cocain.  The  anesthetic  effect  pro- 
duced by  this  method  will  usually  be  found  sufficient  to  partly 
or  entirely  divest  the  operation  of  pain,  and  of  such  duration  as 
to  seldom  require  repetition  except  at  subsequent  stages  of  the 
operation. 

Electrolysis  (cataphoresis)  will  effect  rapid  diffusion  of  the 
cocain,  the  solution  of  cocain  being  placed  on  cotton  against  the 
sides  and  margins  of  the  gums.  A  weak  current  of  electricity 
should  be  used,  the  positive  pole  being  applied  to  the  cotton  and 
the  negative  pole  to  the  cheek  or  held  in  the  hand  of  the  patient. 
The  time  the  method  requires  is  the  objection  to  its  use. 


Collar  Crowns  Hygienically  Considered. 

The  principal  argument  against  collared  or  ferruled  crowns 
is  that  they  are  productive  of  irritation  to  the  peridental  mem- 
brane, ultimately  causing  its  absorption  and  the  exposure  of  the 
collar.  This  would  be  theoretically  and  practically  true  of  a 
rough  or  porous  substance  encircling  the  root,  or  of  an  imper- 
fectly and  unskilfully  adjusted  or  cemented  ferrule  or  collar, 
which  would  by  its  presence  hold  a  position  analogous  to  a  cal- 
careous deposit;  but  it  could  not  be  fairly  predicated  concerning 
a  perfectly  fitted  collar,  forming  at  its  edge  a  smooth  and  im- 
perceptible union  with  the  sides  of  the  root,  and  presenting  a 
uniform  and  benign  surface  to  the  investing  membrane.  In  the 
case  of  perfectly  adapted  collars,  when  any  irritation  of  the  mem- 
brane exists,  it  will  be  found  to  result  from  such  causes  as  usually 
produce  it  when  the  natural  crowns  are  present,  namely,  dental 
concretions.  A  tarnished  and  unclean  condition  of  the  surface  of 
the  gold  of  the  collar  will  produce  irritation  of  the  membranes, 
which  is  a  matter  independent  of  the  collar  itself,  and  easily  reme- 
died by  cleansing  and  polishing  the  surface.  Where  an  acid  condi- 
tion of  the  secretions  of  the  mouth  exists,  a  collar  of  platinum  is 


82  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

suggested  in  preference  to  gold,  as  this  metal  will  not  be  affected, 
but  will  constantly  present  an  untarnished  surface. 

When  evidences  of  a  tendency  to  pyorrhea  alveolaris  exist,  a 
collar  adjusted  to  support  bridge-work  should  not  be  extended 
under  the  gum-margin ;  instead  the  edge  is  best  placed  considerably 
above  the  gum-margin,  so  as  to  better  permit  treatment  of  the 
disease. 


CHAPTER    VI. 

Gold  Collar  Crowns  with  Porcelain  Fronts. 

incisors  and  cuspids:  constriction  and  adaptation  of  the 
cap— the  post— method  of  forming  posts  to  accurately  fit 
canals— post  and  cap— selection  and  adaptation  of  porce- 
lain front — protecting  the  incisal  edge— backing  the 
porcelain  front — preparation  for  investment— soldering 
and  finishing  bicuspids  and  molars— dr.  stowell's  method 
of  applying  a  countersunk  tooth  or  a  logan  crown- 
crowning  in  cases  of  abrasion— gold  crowns  with  porce- 
lain fronts  for  teeth  with  living  pulps. 

This  style  of  crown  for  incisors  and  cuspids,  as  originally  made 
by  Dr.  C.  M.  Richmond,  and  with  which  his  name  has  become 
associated,  consisted  of  a  cap  for  the  root,  formed  of  a  band  of 
gold  capped  with  platinum,  on  which  was  soldered  a  tooth  with 
a  slot  in  the  center  between  the  pins.  Through  this  slot  and  the 
center  of  the  cap  a  screw  passed,  which  entered  into  a  cylinder 
previously  screwed  and  cemented  into  the  root-canal. 

The  form  of  gold  collar  crown  in  general  use  is,  in  principle, 
the  same  as  what  was  formerly  known  in  dentistry  as  a  gold  pivot- 
tooth,  with  the  addition  of  a  gold  collar  for  the  root,  and  having 
the  advantage  of  oxyphosphate  for  its  cementation.  These  im- 
provements enhance  its  value  as  a  crown,  and  materially  change 
the  process  of  its  construction. 

Adjustment  of  the  Collar. — In  making  an  incisor  or  cuspid 
crown  of  this  style,  the  root-canal  is  treated,  the  root  shaped,  and 
a  collar  made  and  fitted  as  described  in  the  preceding  chapter. 
The  collar  is  held  in  position  on  the  root,  a  sharp-pointed  instru- 
ment introduced  inside  of  the  collar,  and  the  line  of  the  surface 
of  the  root  scratched  on  the  metal  around  the  circumference.  The 
collar  is  removed  and  trimmed  a  trifle  flush  to  this  mark  with  small- 
pointed  shears  (Fig.  140).  It  is  adjusted  on  the  root,  and  the 
edge  of  collar  and  root  ground  even,  removing  some  of  the  surface 
of  the  root  if  necessary  for  this  purpose.     In  the  operation  of 

83 


84 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  140. 


grinding,  the  collar  should  be  first  firmly  held  in  position  on  the 
root  at  the  labial  side  while  the  palatal  section  is  ground,  then  at 
the  palatal  while  the  labial  is  being  reduced.  At  the  labial  section, 
the  collar  and  surface  of  the  root  should  be  removed,  so  as  to  be 
invisible  if  the  patient  exposes  the  gum-margin  in  speaking  or 

laughing.  In  cases  where  there  is  no 
such  exposure,  a  proportionate  amount 
more  of  the  collar  and  root  may  re- 
main; this  is  often  desirable,  as  it  af- 
fords additional  strength.  The  work 
will  then  present  an  appearance  re- 
specting the  collar  such  as  is  shown  in 
Fig.  141  and  at  A,  Fig.  145. 

As  the  sides  of  the  collar  are  parallel 
with  the  line  of  the  cervical  section  of 
the  root,  the  edge  of  the  collar  at  the 
palatal  side  forms  a  right  angle  with 
the  surface  of  the  end  of  the  root 
(A,  Fig.  141).  In  close  occlusions 
this  is  liable  to  give  a  shape  to  the  fin- 
ished crown  at  that  part  quite  percept- 
ible and  objectionable  to  the  patient. 
This  can  be  avoided  by  slightly  round- 
ing off  the  palatal  edge  of  the  root  to 
the  form  illustrated  at  B,  Fig.  142. 
The  collar  is  then  slit  two-thirds  across, 
as  outlined  at  S,  Fig.  142,  the  edges 
beveled  slightly,  lapped,  fitted  on  the 
root,  pressed  and  burnished  to  the 
part,  and  soldered.  In  the  finished 
crown  the  collar  will  then  present 
a  form  nearer  that  of  the  natural 
tooth,  as  illustrated  in  Fig.  143. 

The  top  of  the  collar  that  completes  the  cap  is  made  of  very 
thin  platinum  plate,  about  No.  37  gage  or  1/1000  foil.  The  foil 
is  preferable  when  it  is  desirable  to  have  the  least  possible  space 
occupied  by  the  platinum  at  the  labial  section  of  the  cap.  Thin 
platinum  forming  the  top  to  the  cap  does  not  materially  affect 
the  strength  of  the  finished  crown,  as  that  part  is  reinforced  by  the 
solder  subsequently  applied. 


GOLD  COLLAR  CROWNS  ^YITH  PORCELAIN  FRONTS. 


85 


To  Form  the  Cap  to  the  Collar — A  piece  of  the  platinum  is 
cut,  square  or  round,  considerably  larger  than  the  circumference  of 
the  collar.  The  outer  edge  of  the  collar  is  placed  against  the  plati- 
num and  adapted  to  its  surface  by  slight  pressure  between  the  fin- 
gers. With  the  collar  so  placed  the  edge  of  the  platinum  is  seized 
with  a  clamp.  A  piece  of  solder,  with  flux,  is  placed  on  the  platinum 
outside  of  the  collar  and  against  or  touching  it.  The  whole  is  then 
held  in  the  flame  of  a  Bunsen  burner,  the  solder  fused,  and  collar 
and  top  united  (Fig.  144).  The  quantity  of  solder  applied  must  be 
very  small,  barely  sufficient  to  unite  the  parts.  So  limited,  it  will 
not  flow  over  the  inside  of  the  cap  to  interfere  with  its  fit  on  the 
root.  All  parts  of  the  edge  of  the  collar  and  platinum  should  touch 


Fig.  141. 


Fig.   142. 


Fig.   143. 


Fig.   144. 


before  they  are  soldered,  otherwise  in  subsequent  soldering  the 
seam  is  liable  to  open  up.  Perfection  in  this  part  of  the  work  is 
most  easily  attained  by  first  attaching  the  platinum  to  the  edge  of 
the  collar  at  one  point  with  a  mere  particle  of  solder,  to  retain  and 
position  it,  and  then  readapting  the  rest  of  the  edge  and  completing 
the  soldering.  When  the  collar  and  top  are  united,  the  plati- 
num is  trimmed  to  the  outline  of  the  collar  with  small  shears,  and 
finished  smooth  with  a  corundum-point. 

The  cap  is  next  adjusted  on  the  root.  Should  any  part  of  the 
cap  not  seem  to  go  to  its  position  accurately,  a  little  pressure  with  a 
foot-shaped  foil  condenser  along  the  edge  of  the  collar  at  the  part 
soldered  to  the  top  will  correct  it,  if  the  soldering  has  been 
properly  conducted.  Pressure  is  next  exerted  with  the  finger  on 
the  palatal  side  of  the  cap  to  retain  it  in  position  while  the  labial 
section  is  burnished  to  the  flat  surface  of  the  root.    This  adaptation 


86  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

of  the  platinum  steadies  and  positions  the  cap  on  the  root.     The 
cap  is  then  ready  to  receive  the  post. 

Preparation  of  Canal  to  Receive  Post. — In  a  collar  crown 
of  the  style  described,  the  collar  is  largely  relied  upon  for  reten- 
tion on  the  root,  and  the  post  is  therefore  not  usually  as  impor- 
tant a  part  as  in  a  crown  where  a  partial  collar  or  no  collar  is  used. 
To  receive  the  post,  the  root-canal  is  first  reamed  with  a  Gates-Glid- 
den  drill  and  then  with  suitable  sized  fissure  or  round 
burs  (B,  Fig.  145).     The  orifice  to  the  canal  should 

4  be  slightly  enlarged  with  a  large,  round  bur,  to  give  it 
a  slightly  cup-shape  form.  Into  this  depression  the 
platinum  of  the  cap  to  the  collar  is  to  be  burnished. 
The  object  of  the  depression  is  to  provide  a  space  to 
flow  the  solder  in  around  the  post  to  reliably  attach  it 
to  the  cap,  especially  should  conditions  require  that  the 
end  of  the  post  be  ground  off  close  to  its  surface.     (See  Fig.  146 

Fig.  146.  in  section.) 

Posts. — Platinum  or  iridio-platinumwire, 
preferably  round,  ISTos.  16  to  18  gage — a 
little  smaller  for  laterals  or  other  roots  which 
require  its  reduction — is  used  for  posts.  A 
hollow  post,  the  open  space  in  the  center  of 
which  is  small,  affords  the  advantage  that  it 
can  be  drilled  out  of  the  canal  in  a  compara- 
tively easy  manner  if  for  any  reason  it  becomes  necessary  to  re- 
move the  crown,  as  the  drill  will  follow  the  fine  opening  in  the 
center  of  the  wire.1  The  use  of  posts  made  of  alloys  of  the  base 
metals  is  to  be  condemned  for  this  style  of  work.  The  wire  may 
be  first  rolled  under  a  flat  file,  to  roughen  its  surface.  It  should 
be  slightly  tapered  and  introduced  one-quarter  of  an  inch,  more 
or  less,  up  the  canal,  as  indicated  by  the  conditions  of  the  case 
(Figs.  145  and  147)  respecting  length  of  root,  size  of  artificial 
crown  to  be  mounted,  and  character  of  the  occlusion.  A  long, 
large  crown  or  a  close  occlusion  suggests  a  longer  and  heavier  post 
than  a  small  crown  or  a  more  favorable  occlusion.  If  the  canal  is 
for  any  reason  much  enlarged,  the  point  of  the  post  should  be 
tapered  and  extended  to  its  extremity  in  order  to  strengthen  the 
root  as  well  as  anchor  the  crown.    (See  Part  I,  Chapter  II.)  When 

1  Hollow  posts  are  now  manufactured  and  sold. 


GOLD  COLLAR  CROWS  S  WITH  FORCE  LAIS  FROSTS. 


87 


gutta-percha  is  the  cement  to  be  used  to  attach  the  crown,  a  longer 
post  is  required  than  for  oxyphosphate.  The  post  should  fit  the 
canal  in  such  a  manner  as  to  need  the  presence  of  only  a  small 
quantity  of  the  gutta-percha  to  secure  it  (Fig.  147). 

Method  of  Forming  Posts  to  Accurately  Fit  Canals. — To 
form  a  post  which  will  accurately  fit  a  canal,  especially  canals 
which  for  some  reason  are  considerably  enlarged,  slightly  taper 
the  point  of  a  piece  of  platinum  wire  about  No.  20  to  21  gage  and 
a  half -inch  long.  Fit  it  to  the  extremity  of  the  canal  and  bend 
the  end  of  the  wire  toward  the  labial  side  at  a  right  angle,  to  indi- 
cate its  position  when  inserted  (Fig.  148) ;  tip  the  point  of  the  wire 
with  pure  gold  by  fusing  on  it  a  pellet  of  gold  foil.  Cut  a  strip  of 
platinum  foil  1/1000  gage  about  one-eighth  of  an  inch  wide  and 


Fig.  147. 


Fig.   148. 


Fig.   149. 


A 


B 

an  inch  in  length,  bend  the  end  of  the  strip  of  foil  over  the  end 
of  the  wire  close  to  the  point,  and  solder  the  wire  and  foil  in  a 
Bunsen  flame.  The  tip  of  gold  at  the  point  of  the  wire  on  fusing 
will  attach  the  strip  (A,  Fig.  149).  Xext  wind  the  strip  around  the 
wire,  as  shown  at  B,  Fig.  149,  and  insert  in  the  canal.  The  folds 
of  foil  will  press  down  on  the  wire  in  conformity  to  the  size  and 
shape  of  the  canal,  as  illustrated  at  C,  Fig.  149.  Seize  the  exposed 
portion  of  the  foil  and  wire  firmly  with  small-pointed  pliers,  re- 
move in  position,  and  solder  in  a  Bunsen  flame  with  pellets  of  gold 
foil.  Apply  only  enough  gold  to  unite  the  layers  of  platinum, 
for  if  an  excess  be  used  the  shape  of  the  post  will  be  altered 
and  it  will  not  fit  the  canal.  The  corrugations  on  the  post 
formed  by  the  layers  of  platinum  foil  afford  an  attachment  for 
the  cement. 

Post  and  Cap. — The  post  having  been  formed,  the  cap  is  ad- 


gg  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

justed  on  the  root,  the  platinum  over  the  canal  is  burnished  into 
the  orifice  and  punctured.  The  end  of  the  post  is  seized  between 
the  points  of  wire  pliers  and  the  post  inserted  and  forced  to  posi- 
tion in  the  canal  and  the  correctness  of  its  relations  with  the  cap 
observed  and  decided.  Cap  and  post  are  next  removed,  both  dried, 
slightly  heated,  and  the  surface  of  the  cap  and  extreme  end  of  the 
post  veneered  with  adhesive  wax.  The  cap  and  post  are  again  ad- 
justed to  position  on  the  root,  a  small  pellet  of  the  wax  is  placed 
over  the  end  of  the  post  and  pressed  against  the  surface  of  the  cap 
and  around  the  post.  The  wax  is  chilled  with  water  and  the  cap 
and  post  carefully  removed  and  invested.  The  investment  mate- 
rial should  be  carefully  flowed  into  the  interior  of  the  cap,  so  as 
to  fill  every  crevice.  When  set,  the  investment  is 
trimmed  and  reduced  to  as  small  a  size  as  permissible 
(Fig.  150).  It  is  next  heated  and  solder  flowed  into 
the  depression  about  the  post  flush  with  the  surface  of 
the  cap.  Should  any  extensive  aperture  exist  in  the 
platinum  around  the  post  at  the  orifice  of  the  canal  before  solder- 
ing, a  pellet  of  gold  foil  may  be  gently  pressed  in  the  place  to  aid 
/the  solder  to  cover  the  part.  After  removal  from  the  investment 
and  boiling  in  acid,  the  cap  and  post  are  adjusted  in  position  on  the 
root. 

Selection  and  Adaptation  of  the  Porcelain  Front. — The  adap- 
tation of  the  porcelain  front  to  the  cap  is  next  made,  either  directly 
in  the  mouth,  or  by  the  aid  of  a  model  of  the  case.  When  a  model 
is  to  be  used,  a  bite  in  wax  with  the  cap  in  position  is  first  taken 
and  afterward  an  impression  with  impression-compound,  or  prefer- 
ably plaster,  which  will  remove  the  cap  in  position  and  include  the 
adjacent  teeth,  especially  the  opposite  corresponding  tooth  to  that 
being  crowned,  if  present.  To  permit  easy  removal  of  the  cap 
from  the  model,  if  the  crown  is  to  be  fitted  in  the  mouth  during 
its  construction,  a  little  wax  should  be  placed  with  a  heated  spatula 
around  on  the  inner  surface  of  the  collar  and  the  sides  of  the  post 
also  be  slightly  veneered  with  it.  A  plaster  model  is  made,  and 
the  wax  bite  having  been  adjusted  on  it,  an  articulating  model  is 
also  made. 

The  projecting  end  of  the  post  is  next  cut  off  a  little  above  the 
surface  of  the  cap  with  a  thin  disk  or  cutting  pliers.  The  end  of 
the  post  is  then  reduced  with  a  corundum-wheel  close  to  the  sur- 
face at  the  labial  side,  but  left  slightly  projecting  above  it  at  the 


GOLD  COLLAR  CROTVSS  "WITH  PORCELAIN  FRONTS. 


89 


palatal  for  additional  strength  should  such  a  form  offer  no  ob- 
struction to  the  setting  of  the  porcelain  front  (Fig.  151). 

The  porcelain  front  is  formed  of  a  cross-pin  tooth.  The  shade 
selected  should  be  at  least  as  dark  as  that  of  the  opposite  corre- 
sponding natural  tooth,  if  present,  or,  if  absent,  that  of  the  adjoining- 
teeth.  The  general  form,  while  suitable  in  appearance,  should  lie 
such  as  will  permit  of  proper  adaptation  without  ex-  pIG  151. 
cessive  reduction  by  grinding.  The  curve  of  the 
sides  toward  the  base  should  be  such  that  when  the 
front  is  ground,  the  base  shall  not  greatly  ex- 
ceed in  width  the  surface  of  the  cap,  and  the  pins 
be  located  so  that  their  strength  shall  not  become 
impaired  in  the  required  removal  of  the  porcelain  for 
the  proper  adjustment  of  the  front. 

There  are  two  methods  of  setting  the  porcelain  front  to  the  cap. 
In  the  first  method  the  front  is  ground  to  position  with  the  base  of 
the  porcelain  closely  fitted  to  the  surface  of  the  cap 
(Fig.  152).    The  palatal  surface  and  incisal  edge  of  the 
front  are  then  backed  with  metal,  invested,  and  soldered 
to  the  cap. 

In  the  second  method,  which  is  preferable,  the  front 
is  fitted  at  the  cervico-labial  section  to  rest  on  the  cap, 
while  the  remainder  of  the  base  is  ground  so  as  to  form 
a  slightly  increasing  space  toward  the  palatal  side  ju-t 
over  the  post  (B,  Fig.  151).  The  cervico-labial  vdge  of 
the  porcelain  front  should  be  placed  even  or  full  with  the 
edge  of  the  collar.  As  the  porcelain  rests  011  the  cap  at  only  one 
point,  it  simplifies  the  work  of  correctly  positioning  the  front  with 
the  other  teeth.  This  space  between  porcelain  and  cap  can  subse- 
quently be  uniformly  filled  with  the  solder  and  greater  continuity 
of  structure  obtained  than  by  the  first  method.  If  a  model  is  used, 
although  it  facilitates  the  operation  of  fitting,  the  exact  alignment 
of  the  front  had  best  be  determined  by  adjustment  in  the  mouth. 

To  Protect  the  Incisal  Edge  of  the  Porcelain  Front. — To  pro- 
tect the  incisal  edge  of  the  porcelain  front  against  fracture  in  such 
way  that  the  gold  shall  be  invisible,  the  porcelain  should  be  ground 
and  beveled  off  to  the  incisal  edge  at  a  proper  distance  from  the 
pins,  as  shown  in  Figs.  151  and  152;  also  at  A,  Fig.  153.  In  the 
final  finishing  the  gold  is  brought  on  a  straight  line,  or  nearly  so, 
with  the  edge  of  the  porcelain,  as  shown  at  B,  Fig.  153.     By  tin* 


90 


CROWN-,  BRIDGE-,  A*W   PORCELAIN-WORK. 


Fig.  153. 


f^i&s^ 


B 


plan  the  porcelain  is  protected  and  the  gold  is  rendered  invisible 
when  viewed  from  the  front. 

Backing  the  Porcelain  Front. — The  backing  of  the  porcelain 
front  should  fit  the  porcelain  closely  and  furnish  the  greatest  pos- 
sible strength  to  the  finished  crown.  It  is 
made  of  platinum  or  gold.  Platinum  im- 
parts a  slightly  blue,  and  gold  a  yellow 
shade  to  the  porcelain.  The  best  platinum 
for  the  purpose  is  in  the  form  of  foil 
1/1000  gage,  as  such  a  thickness  permits 
\  ^^^y        *ne  metal  to  be  closely  adjusted  to  the  sur- 

face of  the  porcelain. 

The  front  is  first  divested  of  every  par- 
ticle of  wax, — best  done  by  immersing  it  in 
boiling  water.  The  platinum  is  applied  to 
extend  in  one  piece  over  the  back  of  the 
front  down  on  the  base  as  far  as  possible 
between  the  porcelain  and  the  top  of  the 
cap  without  interfering  with  the  posi- 
tioning of  the  front.  The  ends  of  the  pins 
are  first  pressed  against  the  platinum  and  its  surface  indented. 
Holes  are  punched  through  the  indentations  and  the  platinum 
closely  adapted  to  the  surface  of  back  and  base  (B,  Fig.  151)  to 
carry  the  solder  and  fill  the  space  between  the  porcelain  and  cap. 
The  platinum  is  next  trimmed  off  even  with  the  edge  of  the  porce- 
lain, except  at  the  incisal  section,  where  it  is  cut  even  with  the 
back  of  the  front  at  the  line  C,  Fig.  151  giving  the  backing  when 
off  the  front  the  form  shown  at  D.  The  incisal  section  and  only 
the  back  of  the  front  is  then  additionally  backed  with  a  piece  of 

22-carat  gold  plate,  or  of  platinum  and 
gold,  about  INTo.  30  gage.     Holes  for  the 
pins  are  punched  and  countersunk  in  the 
plate,  which  is  cut  and  fitted  the  width  of 
the  front  and  only  long  enough  to  extend 
past  the  pins,   and  to  cover  and  extend 
slightly  beyond  the  edge  of  the  incisal  sur- 
face.      The    gold    will    then    present    a 
form  such  as  is  shown  at  E,  Fig.  151.     Two  or  three  holes  are 
punched  from  the  inner  side  of  the  hacking  outward  above  the  pins, 
as  shown  at  E,  Fig.  154,  to  enable  the  solder  to  easily  enter  and 


Fig.  154. 


GOLD  COLLAR  CROWNS  WITH  PORCELAIN  FRONTS.  Q\ 

flow  between  the  backings.  The  platinum  foil  backing  having 
been  closely  adjusted  to  the  surface  of  the  porcelain,  the  gold 
backing  is  placed  over  it  and  the  pins  bent  down  on  the  surface  in 
either  of  the  positions  shown  at  A  and  B,  Fig.  155.  When  bent 
as  at  A,  they  assist  in  retaining  the  solder  in  position  in  soldering 
and  thickening  the  backing  at  that  point,  if  that  is  desirable. 

When  the  first  or  inside  backing  is  preferably  formed  of  pure 
gold  instead  of  platinum  foil,  it  is  applied  in  the  same  manner  as 
the  platinum,  but  must  be  of  about  No.  37  gage. 
Platinum-lined  gold  nearly  as  thin  as  platinum 
can  be  used  instead  of  pure  gold,  with  which,  by 
placing  the  gold  side  toward  the  porcelain,  the 
same  effect  on  the  shade  can  be  obtained  as  with 
'pure  gold. 

Other  methods  of  backing  are  in  use.  Of  these, 
one  which  may  be  advantageously  practiced,  espe- 
cially when  the  back  of  the  porcelain  front  is  ground  quite  short, 
is:  First  back  the  front  and  reinforce  the  incisal  section  with 
pure  gold  plate  in  one  piece  of  about  No.  30  to  32  gage.  Next 
cover  the  base  with  platinum  foil  of  at  least  1/2000  gage  by  heat- 
ing the  porcelain,  varnishing  the  base  with  adhesive  wax,  and  press- 
ing the  foil  on  the  surface.  By  again  heating  the  front  and  foil 
and  by  exerting  uniform  pressure  over  the  entire  surface  with  a 
napkin  or  a  pellet  of  cotton,  the  foil  will  be  closely  cemented 
against  the  surface  of  the  porcelain  and  the  intervening  varnish 
of  wax  imperceptible.  The  surplus  foil  is  trimmed  off  close  to  the 
edge  of  the  base  of  the  front. 

Another  method  is  to  first  back  with  either  platinum  or  gold 
plate  of  No.  30  to  32  gage  only  the  palatal  side  of  the  front,  apply 
the  thin  platinum  foil  to  the  base,  and  as  the  crown  is  ready  for 
investment,  place  and  cement  in  position  with  wax  a  piece  of 
22-carat  gold  plate  over  the  incisal  section,  leaving  the  ends  of  the 
plate  extending  out  sufficiently  beyond  the  edge  of  the  porcelain 
to  retain  it  in  position  in  the  investment. 

The  metal  used  in  backing  a  front  should  be  annealed  during 
the  process,  and  the  portion  which  comes  in  contact  with  the  porce- 
lain closely  adapted  by  pressure  and  burnishing.  Close  contact 
affords  better  support  to  the  porcelain  and  greater  continuity  of 
structure  to  the  crown.  When  plate  is  used  for  the  backing  a  die 
may  be  used,  to  assist  in  adapting  it  closely  to  the  porcelain.     An 

8 


92  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

intaglio  die  sufficient  for  the  purpose  can  be  quickly  formed  by 
pressing  the  back  of  the  front  against  the  surface  of  a  piece  of  im- 
pression-compound, Dental  Lac,  or  sealing-wax,  chilling  the  mate- 
rial, and  removing  the  front.  The  plate  can  be  swaged  against 
the  surface  of  the  porcelain  in  this  die.  Another  method  is 
to  place  the  porcelain  tooth  with  the  backing  on  it  in  position 
wrapped  in  tissue  paper  in  a  swager.  The  pressure  should  be 
gradually  increased  from  light  to  heavier  blows  from  the  hammer 
on  the  plunger.  In  backing  porcelain  fronts  the  metal  used  should 
be  neatly  trimmed  to  the  sides.  It  must  not  be  bent  over  the  edges 
closely,  especially  at  less  than  a  right  angle,  as  expansion  and  con- 
traction of  both  porcelain  and  solder  are  very  liable  to  cause 
fractures. 

Preparation  for  Investment — The  porcelain  front  when 
backed  is  adjusted  on  the  cap.  Should  the  metal  backing  the  base 
of  the  front  interfere  with  its  proper  adjustment  on  the  cap,  as 
is  liable  to  occur  at  the  cervico-labial  section,  it  should  be  thinned 
with  a  small  corundum  cone,  or  entirely  removed  at  the  obstruct- 
ing point,  and  that  portion  of  the  porcelain  allowed  to  rest  directly 
on  the  cap.  The  front  is  first  attached  to  the  cap  with  only  a  small 
quantity  of  adhesive  wax,  until  its  alignment  is  quite  accurately 
determined,  when  hard  wax  is  added  to  more  securely  retain  it. 
The  whole  is  then  chilled  in  cold  water  and  a  final  adjustment 
made  to  positively  assure  its  correctness.  Before  investing,  addi- 
tional wax  is  added  to  the  metallic  parts  of  the  crown  sufficient  to 
impart  to  them  the  desired  form  when  soldered  and  also  to  allow 
additionally  a  slight  excess  for  finishing.  A  little  wax  is  generally 
placed  on  the  sides  of  the  collar  at  the  cervical  section  of  the  porce- 
lain front,  especially  where  any  portion  of  it  projects  over  the  line 
of  the  collar,  for  the  purpose  of  providing  space  in  the  investment 
for  the  solder  to  flow  and  contour  the  part. 

When  the  porcelain  projects  beyond  the  edge  of  the  collar  at 
Fig.  156.  the  cervico-labial  section,  as  frequently  occurs  in  cases 
of  cuspids,  a  space  is  left,  such  as  is  shown  at  A,  Fig. 
156.  This  space  should  be  evenly  filled  with  gold 
solder  when  the  front  is  being  attached  to  the  cap.  To 
accomplish  it  the  platinum  foil  applied  to  the  base  of 
the  porcelain  should  be  extended  over  the  whole  sur- 
face and  slightly  beyond  the  edge  of  the  porcelain  at 


GOLD  COLLAR  CROWXti  ^YITH  POIICELAIX  FROXTS. 


93 


Fig.  157. 


the  cervico-labial  section.  The  open  space  is  filled  and  shaped 
evenly  with  wax  a  little  flush  at  the  edge  of  the  collar.  To  assist 
in  drawing  the  solder  to  the  part,  a  narrow  strip  of  Xo.  30  rolled 
gold  foil  may  be  neatly  adapted  over  the  surface  of  the  wax. 
Should  the  foil  extend  slightly  beyond  the  edge  of  the  wax  and 
rest  on  the  surface  of  the  porcelain,  it  will  not  cause  fracture  if 
closely  adapted  to  the  surface.  In  such  cases  the  flowing  of  solder 
to  the  part  is  further  facilitated  by  forming  an  aperture  either  on 
the  bottom  or  on  each  side  of  the  investment,  which  will  expose 
it  and  if  necessary  permit  solder 
to  be  applied  directly.  This  can  be 
most  easily  done  by  attaching  a  small 
cone  of  wax,  as  indicated  by  the 
dotted  lines  in  Fig.  157,  before  in- 
vestment, thus  forming  a  channel, 
the  orifice  of  which  can  afterward  be 
shaped  or  enlarged. 

Investment.  —  Calcined  marble- 
dust  and  plaster  is  the  generally  preferred  material  for  investment. 
It  is  used  in  the  proportions  of  two  part-  of  marble-dust  to  one  of 
plaster.  Potassium  sulfate  may  be  added  to  the  water  to  hasten 
the  setting,  in  the  proportion  of  one  small  teaspoonful  to  a  pint  of 
water.  The  crown  is  first  wet  by  dipping  in  water  and  then  a 
little  of  the  investment  material  is  placed  in  the  inside  of  the  cap. 
Another  portion  is  next  placed  on  a  piece  of  paper  in  the  form  of 
a  small  mound,  and  the  crown  is  gently  pressed  into  it  until  all  the 
parts  are  covered  except  the  wax  on  the 
palatal  side  of  the  backing.  When  the  in- 
vestment has  set,  it  is  trimmed  and  reduced 
in  size  as  much  as  it  properly  can  be  and  the 
investment  material  removed,  so  that  the 
metallic  parts  of  the  crown  are  slightly  ex- 
posed at  the  side,  as  shown  in  Figs.  157  and 
158.  The  wax  is  removed  by  pouring  boiling  water  on  the  in- 
vestment. Instruments  should  not  be  used  to  remove  wax,  as  they 
are  liable  to  disturb  delicately  adjusted  parts.  Borax  ground  fine, 
mixed  with  water,  or  liquid  flux,  is  applied  with  a  brush  to  the 
metallic  parts  and  in  the  seams  before  heating.  When  Parr's 
fluxed  wax  is  used  for  the  benefit  of  the  flux  it  contains,  the  wax 


Fig.  158. 


94  CROWN-,    BRIDGE-,  AND  PORCELAIN-WORK. 

is  allowed  to  burn  out  as  the  investment  is  heated.  The  objection 
to  burning  wax  out  is  that  the  resulting  debris  is  liable  to  pit  the 
solder  slightly.   • 

Soldering  and  Finishing — The  investment  should  be  first 
dried  and  heated  to  a  dull  red  over  a  Bunsen  flame  (see  Part  V, 
Chapter  IV)  and  then  removed  to  a  soldering-block.  Gold  solder, 
cut  into  small  pieces,  in  quantity  only  sufficient  to  fill  interstices 
and  unite  front  to  cap,  is  placed  in  and  over  the  aperture  between 
the  front  and  cap.  The  solder  should  have  been  previously  im- 
mersed in  borax  finely  ground  in  water  and  then  dried;  or,  after 
it  is  placed  in  position,  it  should  have  a  small  quantity  of  calcined 
borax  or  Parr's  flux  sprinkled  over  it.  By  heating  the  investment 
uniformly,  especially  underneath,  and  in  the  direction  A,  Figs. 
157  and  158,  with  the  large  flame  of  a  gas  blowpipe,  the  solder  is 
melted  and  gradually  flowed  downward  and  between  the  front  and 
cap  and  in  the  interstices  between  the  pieces  of  metal  forming  the 
backing.  More  solder  is  added  by  degrees  and  fused  in  this  manner 
until  the  spaces  between  the  porcelain  and  cap  and  at  the  sides  are 
filled  in  and  continuity  of  structure  assured.  After  letting  the  body 
of  the  investment  cool  slightly,  so  as  not  to  draw  bach  the  solder 
that  has  been  already  fused  in  the  deep  portion  of  the  investment, 
additional  solder  is  placed  on  the  backing  and  cap,  and  with  a 
small-pointed  flame  flowed  over  these  parts.  Only  sufficient  gold 
should  be  applied  to  properly  contour  the  parts.  When  soldered 
the  investment  should  be  allowed  to  cool  slowly,  the  crown  re- 
moved and  boiled  in  acid  to  thoroughly  remove  the  borax,  and 
then  trimmed  and  polished.  In  finishing,  the  motion  of  the 
wheels  in  trimming  and  polishing  should  be  so  directed  that  the 
edge  of  the  metal  adjusted  to  the  porcelain  is  brought  against 
the  surface.  Fig.  159  represents  the  completed 
Fig.  159.       crown. 

A  more  expeditious  method  of  constructing  this 
style  of  crown,  which  is  practiced  to  some  extent, 
is  to  unite  the  post  and  porcelain  front  to  the  cap 
in  one  soldering,  as  f ollows :  After  having  fitted 
the  post  to  the  root-canal  and  cap,  lay  the  post  aside. 
The  porcelain  front  is- next  ground  and  adapted  to  the 
cap,  properly  backed  with  metal,  attached  in  position 
on  the  cap  with  wax  cement,  adjusted  in  the  mouth, 
and  removed.     The  pin  is  next  warmed  and  placed  in  position  by 


GOLD  COLLAR  CR0WX8  WITH  PORCELAIN  FRONTS. 


95 


passing  the  end  through  the  hole  at  the  inside  of  the  cap  into  the 
wax  attaching  the  porcelain  front.  The  whole  is  next  adjusted  in 
the  month  to  get  the  exact  line  of  the  pin,  carefully  removed,  in- 
vested, and  soldered. 

Bicuspids  and  Molars. — Bicuspids  crowned  by  this  method 
will  have  greater  strength  if  a  portion  of  the  palatal  section  of  the 
natural  crown  is  preserved  (Fig.  27),  because  of  the  support  it 
affords  to  the  collar  which  will  cover  it. 

The  end  of  the  root  is  capped  after  the  manner  of  the  typical 
central  already  described,  one  or  two  pins  being  used  in  the 
canals  as  required.  Where  only  one  pin  is  used,  it  is  best  inserted 
in  the  palatal  canal.  A  porcelain  cuspid  tooth,  or  a  bicuspid  front, 
is  then  ground,  backed,  and  adjusted  on  the  cap  to  represent  the 
labial  aspect,  and  secured  with  wax.  It  is  carefully  adjusted 
in  the  mouth,  and  the  occluding  edge  of  the  porcelain  is  ground 
to  clear  the  antagonizing  teeth  (A,  Fig.   160).      With  a  die  of 


Fig.    1G0. 


Fig.    161. 


Fig.    162. 


Fig.    ]f>4. 


Fig.   165. 


suitable  size  representing  the  occluding  surface  of  a  bicuspid,  as 
illustrated  in  Fig.  161,  a  piece  of  pure  gold  plate  (about  jNTo.  30 
gage)  is  swaged  (Fig.  162)  and  the  cusps  filled  in  with  18-carat 
solder  or  gold  plate.1  The  cap  is  then  trimmed  (Fig.  163), 
ground,  and  fitted  to  the  occluding  edge  of  the  porcelain  front 
(Fig.  164)  in  proper  position  as  regards  occlusion,  and  the  wax 
attaching  it  is  shaped  to  the  contour  of  the  crown  (A).  A  piece 
of  very  thin  gold  plate  or  of  "No.  60  foil  (B)  is  then  adjusted  on 
each  approximal  side  of  the  crown,  which  is  invested  (Fig.  165). 
The  long  ends  of  the  side-pieces  of  gold  plate  are  designed  to  retain 

1  A  hard-flowing  solder  is  best  for  use  in  filling  cusps  to  protect  porcelain 
fronts  to  crown-  or  bridge-work.  It  is  made  of  two  parts  18-carat  gold  plate 
and  one  part  18-carat  solder.  The  plate  and  solder  should  be  melted  together 
and  rolled  out  quite  thin  and  kept  ready  for  use  (Part  V.  Chapter  I). 


96  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

them  in  position,  as  the  investing  material  may  be  removed  from 
the  portion  inclosing  the  sides  of  the  crown  (A).  Mica — isinglass 
— may  also  be  used  as  suitable  for  this  purpose  instead  of  gold. 
In  the  process  of  soldering,  the  solder  is  placed  in  the  aperture  at 
B,  and  the  flame  of  the  blowpipe  being  directed  on  the  exposed 
sides  of  the  gold  at  A,  the  solder  is  flowed  into  every  part,  form- 
ing perfect  continuity  of  structure  of  the  metallic  portion  of  the 
crown.  If  this  aperture  at  A  is  left  open  without  the  gold  or  mica, 
and  the  solder  is  first  flowed  in  the  interstices  as  described  in 
soldering  an  incisor  crown,  the  remaining  solder  necessary  to  con- 
tour the  part  can  be  added,  if  the  pointed  flame  is  used  and  not 
applied  to  the  other  portions  of  the  crown  and  investment.  In 
finishing,  the  surplus  gold  is  trimmed  to  the  contour  of  a  bicuspid 
tooth.     Fig.  166  represents  the  finished  crown. 

In  difficult  cases  and  occlusions  the  work  is  simplified  by  first 
soldering  the  porcelain  front  to  the  cap.  The  crown  is  then  ad- 
justed in  the  mouth  and  the  porcelain  ground  to  properly  clear  the 
occluding  teeth  and  allow  space  for  the  gold  cap.  The  gold  cap 
is  next  adjusted  in  position,  the  parts  shaped  with  wax  inserted, 
and  the  soldering  completed.  To  form  the  occluding  and  palatal 
section  of  the  crown  in  exact  accordance  with  the  occluding  teeth, 
where  the  occlusion  is  abnormal,  the  parts  are  to  be  first  neatly 
modeled  in  hard  wax  and  a  die  cast  of  the  occluding  surface. 
From  this  a  cap  can  be  stamped  that  may  be  easily  fitted  to  prop- 
erly occlude. 

The  method  described  produces  a  perfect  and  artistically  formed 
crown,  but  simpler  and  quicker  methods  are  practiced.  One  of 
these  is  to  build  up  the  palatal  cusp  with  several  pieces  of  gold 
plate,  which  have  been  previously  melted  into  the  form  of  small 
balls  and  flattened  out  on  an  anvil.  These,  laid  in  position  and 
united  with  solder,  are  shaped  in  finishing  to  represent  the  palatal 
cusp  (Fig.  167).  The  porcelain  front  should  be  backed  so  that 
the  solder  can  be  flowed  over  its  occluding  edge. 

Another  method  is  to  extend  the  palatal  part  of  the  collar  down, 
as  shown  in  Fig.  168,  and  then  fill  in  the  space  with  solder.  In 
finishing,  the  gold  is  trimmed  to  the  form  of  the  crown.  As 
much  as  possible  of  the  natural  crown  should  be  left  at  the  palatal 
side  of  the  collar,  the  exposed  edge  of  which  may  be  slit  and 
brought  in  against  the  side  and  soldered  to  give  contour.  With 
this  form  of  collar  one  pin,  in  the  palatal  root-canal,  is  sufficient. 


GOLD  COLLAR  CR01YXS  WITH  PORCELAIN  FRONTS. 


97 


It  should  be  allowed  to  extend  out  of  the  cap  enough  to  just 
touch  the  lower  teeth  when  they  are  occluded.  The  exposed  end 
of  the  pin  will  be  an  exact  guide  as  to  the  amount  of  solder  re- 
quired to  form  the  grinding-surface.     In  this  and  in  the  method 


Fig.    1G6. 


Fig.    1G7. 


Fig.    168. 


Fig.    169. 


Fig.  170. 

W  v  ,      R 


previously  described,  the  porcelain  front  may  be  soldered  and  the 
palatal  cusp  formed  in  the  one  investment. 

A  faulty  method  of  forming  bicuspid  crowns,  especially  in  a 
close  occlusion,  and  one  to  avoid,  is  the  shap- 
ing of  the  palatal  side,  as  shown  at  W,  in 
Fig.  170.  The  occluding  surface  should  be 
shaped  so  that  the  cusp  of  the  occluding 
tooth  shall  be  interlocked  in  occlusion,  as 
illustrated  at  E,  Fig.  170,  instead  of  glanc- 
ing off.  In  the  latter  event,  the  root  is  liable 
in  time  to  be  forced  outward  and  loosened. 

For  a  description  of  the  Hollingsworth  method  of  attaching  a 


Fig.  171. 


Fig.  172. 


Fig.  173. 


porcelain  facing  to  a  gold  cap  the  reader  is  referred  to  Part  III, 
Chapter  XIV. 

The  method  of  construction  of  molar  crowns  with  porcelain 
fronts  is  similar  to  that  for  bicuspids  (Fig.  169). 


98  CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 

Saddle=back  Tooth. — The  saddle-back  tooth  is  a  porcelain  tooth 
in  which  the  base  curves  in  an  unbroken  line  from  the  buccal 
surface  at  the  neck  to  the  heel  at  the  palatal  side,  without  any 
shoulder,  the  pins  being  inserted  as  shown  in  Fig.  171.  The  base 
of  the  porcelain  tooth  selected  should  be  at  least  as  large  as  the 
surface  of  the  cap  (Fig.  172).  When  the  tooth  is  ground  and 
fitted,  it  is  backed  flush  to  the  edge  of  the  base  with  pure  gold 
No.  34  gage,  or  platinized  gold  (pure  gold  alloyed  with  2  to  3  per 
cent,  of  platinum),  still  thinner,  waxed  in  position  on  the  cap 
(Figs.  172  and  173),  and  invested  so  that  the  seam  of  wax  shall  be 
fully  exposed.  In  soldering,  the  flame  must  be  directed  under  the 
investment,  to  draw  the  solder  into  the  seam. 

Dr.  Stovvell's  Method  of  Applying  a  Countersunk  Tooth  or 
a  Logan  Crown — A  countersunk  tooth  or  a  porcelain  crown  can 
be  soldered  on  the  cap,  according  to  Dr.  S.  S.  Stowell's  method, 
as  follows  :*     ''The  tooth  used  may  be  a  Logan  crown  or  an  ordi- 


Fig.    174. 


Fig.   175. 


Fig.   176. 


Fig.  177. 


Fig.   178. 


nary  countersunk  tooth,  but  in  most  cases  the  Logan  crown,  hav- 
ing a  strong  pin,  is  preferable.  The  pin  is  first  cut  off,  then  the 
tooth  is  ground  to  fit  on  the  cap,  the  porcelain  and  the  stump  of 
the  pin  being  reduced  alike  evenly  and  smoothly;  after  which  the 
stump  of  the  pin  is  ground  with  a  small  wheel  below  the  surface  of 
the  porcelain  (Fig.  174).  The  tooth  is  then  invested  (Fig.  175) 
and  pure  gold  fused  on  to  the  platinum  pin,  and  while  in  a  fluid 
state  it  is  'spatted'  down  flat  with  a  wax  spatula  (Fig.  176). 
The  gold  is  then  filed  or  ground  down  even  with  the  porcelain, 
and  at  the  palatal  border  the  tooth  is  ground  to  bevel  back  'until 
the  gold  is  reached  (Fig.  177).  The  tooth  is  then  secured  in 
place  on  the  cap  with  wax  cement  (Fig.  178),  the  case  invested, 
and  heated  until  the  wax  has  melted  and  burned  out.  A  small 
clipping  of  thin  platinum  plate  is  crowded  into  the  opening  (Fig. 
179)  caused  by  the  grinding  of  the  bevel  on  the  crown.     The 


1  Dental  Cosmos,  vol.  xxix,  page  641. 


GOLD  COLLAR  CROWNS  WITH  PORCELAIN  FRONTS. 


99 


clipping  of  platinum  serves  as  a  lead  for  the  solder,  which  fol- 
lows it  down  into  the  countersunk  cap,  around  the  ends  of  the 
dowels,  and  finally  attaches  itself  to  the  pure  gold  already  at- 
tached to  the  stump  of  the  platinum  pin.  Fig.  180  represents 
the  completed  crown.  A  sectional  view  of  a  like  crown  (Fig. 
181)  also  shows  the  organization  in  detail.  A  porcelain  crown 
can  be  used  to  represent  any  of  the  teeth  in  the  same  manner. 
(See  Figs.  182  and  183.)" 


Fig.    179. 


Fig.   ISO. 


^j   '-,- 


Fig.  181. 


Fig.    182. 


Fig.    183. 


For  the  construction  of  crowns  of  the  last  two  styles  described, 
considerable  space  between  the  surface  of  the  end  of  the  root  and 
the  occluding  teeth  is  required,  as  a  shallow  intervening  body  of 
porcelain,  unprotected  by  metal,  is  liable  to  fracture. 

Crowning  in  Cases  of  Abrasion. — In  a  case  of  extensive  abra- 
sion of  the  incisal  edges  of  the  anterior  teeth,  with  Pjc  lg4 
pulp  living  though  considerably  calcified  in  the  coro- 
nal section,  crown-work  to  restore  the  length  and 
form  of  the  teeth  is  best  performed  by  removing  a 
portion  of  the  labial  aspect  of  the  natural  crown  and 
then  forming  the  artificial  crown  similar  to  a  gold 
collar  crown  with  a  porcelain  front  without  the  pin. 
Fig.  184  gives  an  outline  of  the  construction  of  such 
a  crown.  If  a  case  should  suggest  the  necessity  of  a 
pin,  a  short  one  can  be  inserted  between  the  line  of 
the  pulp-chamber  and  the  palatal  wall. 

In  case  the  tooth  is  pulpless,  the  canal  can  be  opened  up  and  the 
post  extended  into  the  root  of  the  tooth. 

The  incisal  edge  of  the  porcelain  should  be  well  protected  by 
the  use  of  clasp  gold  and  solder  instead  of  the  ordinary  gold  plate. 
When  an  incisal  surface  of  considerable  thickness  is  suggested,  it 
is  best  built  to  the  desired  depth  after  the  first  protecting  piece 
has  been  soldered,  by  applying  successive  layers  of  plate  rolled 


100  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

thin,  of  the  size  of  the  incisal  edge,  each  being  perforated  with  two 
or  three  holes  with  punch  forceps,  so  that  the  solder  shall  more 
easily  flow  between  and  unite  them.  (See  article  on  "Gold  Tips," 
Chapter  XV.) 

Gold  Crowns  with  Porcelain  Fronts  for  Teeth  with  Living  Pulps. 

In  the  anterior  teeth,  in  case  of  atrophy  or  erosion,  or  where 
decay  has  destroyed  the  approximal  sides  of  a  tooth  in  such  a 
manner  that  crowning  is  considered  the  most  desirable  opera- 
tion to  perform,  the  pulp  is  frequently  found  unexposed  and  in 
a  normal  condition.  The  importance  of  its  preservation  in  such 
a  case  is  unquestionable. 

The  crowning  of  such  cases  with  gold  jacket-crowns,  carrying 
a  porcelain  front  attached  with  solder,  is  generally  a  questionable 
procedure.  The  room  required  for  the  gold  and  the  small  space 
left  for  the  porcelain,  together  with  the  difficulty  of  securely 
attaching  the  latter,  render  such  a  construction  rarely  practicable. 
Jacket-crowns  for  such  cases  are  now  best  made  of  platinum  and 
porcelain,  to  which  the  reader  is  referred  (Part  IV,  Chapter  VI). 
The  construction  of  gold  crowns  with  porcelain  inlays  for  bicus- 
pids is  also  described  in  the  same  chapter,  and  in  the  account  of 
the  Hollingsworth  System  (Part  III,  Chapter  XIV). 


CHAPTER    VII. 

All-Gold  Collar  Crowns  for  Bicuspids  and  Molars 
Constructed  in  Sections. 

methods  op  knuckling  the  collar  and  giving  contour— forming 
the  occluding  surface,  methods  nos.  1,  2,  3,  4,  5,  6,  and  7— 
all-gold-crowns  for  incisors  and  cuspids — cases  of  abra- 
SION. 

The  root  and  crown  having  been  properly  prepared,  the  collar 
is  formed  and  adjusted  as  described  at  page  75,  and  the  edge 
toward  the  antagonizing  teeth  trimmed,  to  fully  clear  them  in 
occlusion.  The  collar  is  then  slightly  expanded  toward  the  occlud- 
ing surface  for  better  contour. 


Fig.  185  A. 


Fig.  185  B. 


Fig.  186. 


Methods  of  Knuckling  the  Collar  and  Giving  Contour. If 

the  collar  is  long  enough,  a  contour,  approximately  that  of  a 
natural  tooth,  can  be  imparted  to  the  side  with  the  aid  of  suitable 
pliers,  such  as  are  illustrated  in  Fig.  125,  one  beak  of  which  is 

101 


102 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


rounded  at  the  point  and  shorter  than  the  other.  The  Johnson 
and  Reynolds  forms,  Figs.  185  A  and  185  B,  are  also  useful  for 
shaping  the  plate  and  removing  inequalities  caused  by  the  use  of 
the  first  form.  Contour  may  also  be  given  by  a  mandrel  die,  or 
mold  (Fig.  186).  A  close  knuckling  can  be  insured  by  press- 
ing the  collar  against  the  approximal  tooth  in  the  manner  shown 
in  Fig.  187. 

Methods  of  Forming  the  Occluding  Surface  or  Cap  to  the 
Collar.  Method  No.  1. — The  collar,  having  been  fitted  (Fig.  188  A 
represents  a  typical  case),  is  removed,  filled  with  plaster,  and  ad- 
justed in  position. 

The  antagonizing  teeth,  having  been  covered  with  a  piece  of 
tin  foil,  are  then  occluded  until  the  plaster  sets.  (See  Fig.  188  B.) 
The  collar  is  then  removed.  The  surface  of  the  plaster  inside 
the  collar  will  give  the  impression  of  the  natural  root  or  crown, 


Fig.  187. 


Fig.  188  A. 


Fig.  188  B. 


and  the  outside  that  of  the  antagonizing  teeth.  The  latter  fur- 
nishes an  outline  to  form  the  grinding-surface  of  the  crown. 

The  plaster  at  the  occluding  section  is  then  trimmed  and  shaped 
to  represent  the  cusps  and  fissures  of  the  natural  tooth,  enough  of 
the  surface  being  removed  to  allow  for  the  thickness  of  the  plate 
that  forms  the  cap.  In  shaping,  the  typical  forms  of  grinding- 
surfaces,  illustrated  in  Fig.  199,  can  be  used  as  a  guide. 

A  small  tube  of  copper,  a  trifle  larger  in  circumference  than 
the  crown  under  construction,  is  filled  with  Melotte's  "Moldine," 
and  the  surface  rubbed  with  soapstone.  An  impression  of  the 
lower  portion  of  the  form  of  the  crown  A  to  the  line  B,  Fig.  189, 
is  then  made  in  the  moldine,  and  a  strip  of  paper  wound  around 
the  tube,  extending  about  an  inch  above  the  edge.  Fusible  alloy 
is  then  melted  and  poured  into  the  mold,  thus  forming  a  die.  An 
indentation  is  made  with  a  punch  in  a  block  of  lead,  into  which 
the  die,  when  cold,  is  hammered  slightly  beyond  the  impression 


Fig.  189. 


Fig.  190. 


A 


ALL-GOLD  COLLAR  CROWXS  COXSTRUCTED  IX  SECT10XS.      1Q3 

of  the  edge  of  the  collar.  By  this  method  a  die  and  a  counter- 
die  (Fig-  190)  can,  with  practice,  be  completed  in  five  minutes. 
With  this  die  the  cap  is  then  struck  up  on  the  lead  from  a  flat 
piece  of  plate  and  fitted  to  the  collar.1  A  little  of  the  surface  of 
the  plaster  in  the  collar  may  have  to  be  removed  from  under  the 
cap,  if,  on  trial  in  the  mouth,  the 
model  or  the  cap  is  found  a  little 
flush.  The  crown,  with  the  plaster 
still  inside  the  collar,  is  fixed  in  a 
soldering-clamp  of  one  of  the  forms 
shown  in  Figs.  191,  192,  193,  and 
19 6,  which  holds  the  parts  together 
and  permits  the  flame  to  reach  all 
points.  One  of  the  points  of  the 
forms  illustrated  in  Fig.  193  may 
be  shaped  to  that  shown  in  Fig. 
196  to  hold  the  cap  in  position  on 
the  collar,  while  the  other  point 
is  used  to  support  the  collar.  With 
the  clamp  (Fig.  191),  the  blow- 
pipe flame  is  the  best.  The  other  forms  suggest  the  Bunsen  flame. 
The  parts  of  the  crown  can  also  be  held  together  for  soldering 
with  iron  wire  in  the  form  of  a  loop  passed  over  the  grinding- 


A.    Fusible-metal 

.lie. 
13,  Counter-ilie. 
C,  Plate  to  form 
the  cap. 


Fig.  191. 


Fig.  192. 


surface,  against  the  sides  of  the  collar,  with  the  ends  twisted  to- 
gether over  the  aperture  of  the  neck  of  the  crown.  Xo  more 
solder  should  be  used  than  is  necessary  to  unite  the  parts  or  give 
any  required  contour,  as  an  excess  necessitates  additional  labor  in 
finishing:. 


1  For  a  description  of  the  use  of  Dental  Lac  to  form  molds  for  the  purpose 
of  swaging  caps,  etc.,  see  Part  V,  Chapter  III. 


104: 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  193. 


Method  No.  2. — If  the  crown  is  not  to  be  contoured  with  the 
aid  of  the  solder,  when  the  cap  is  struck  up,  melt  solder  into  the 

cusps,  and  then  adjust  the  cap  in  position 
on  the  collar,  for  which  purpose  some  of 
the  plaster  underneath  the  cap  must  be 
removed.  A  jet  of  flame  from  the  blow- 
pipe is  then  thrown  upon  it  in  such  a 
maiiner  as  will  cause  the  solder  to  flow 
down  on  the  edge  of  the  collar  and  fill 
the  seam  from  the  inside.  The  objection 
to  this  method  is  that,  when  a  large  por- 
tion of  the  natural  crown  is  inclosed  by 
the  gold,  the  solder  will  occasionally 
alter  the  inside  form  of  the  fitted  cap, 
thereby  interfering  with  its  adjustment, 
which  is  a  defect  troublesome  to  correct. 
Method  No.  3. — This  method  is  spe- 
cially suitable  in  cases  where  all  or  nearly 
all  of  the  grinding-surf  ace  of  the  natural 
crown  is  present  or  where  the  bite  is 
close.  Adjust  the  collar  in  the  mouth, 
and,  with  a  small  piece  of  wax  or  im- 
pression-compound pressed  upon  it,  take 
an  impression  and  "bite,"  in  which 
the  collar  shall  be  imbedded  and  re- 
moved. Witlf  this  a  model  and  articu- 
lation are  made  and  the  form  of  the  cap 
shaped  in  wax.  An  impression  of  the 
cap  is  then  made,  either  in  moldine  in 
a  soft  state  in  a  tube,  or  in  plaster,  and 
a  die  cast.  The  cap  is  stamped  on  this 
die,  then  adapted  to  the  collar  by  the 
model,  and  the  crown  finished.  This 
method1  can  be  adopted  when  it  is  pre- 
ferable to  construct  the  crown  between 
the  visits  of  the  patient,  after  having 
first  made  and  fitted  the  collar. 
Method  No.  Jf. — In  utilizing  a  tooth  as  an  abutment  in  bridge- 


1  Dr.  N.  W.  Kingsley's  method. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.      105 

work  when  all  or  nearly  all  of  the  occluding  surface  of  the  natural 
crown  is  present  and  for  any  reason  very  little  of  it  can  be  re- 
moved, a  practical  method  of  construction  is  to  mark  the  out- 
line of  the  occluding  surface  on  the  inner  surface  of  the  collar; 
then  remove  the  collar  and  trim  so  as  to  leave  a  border  of  about 
one-sixteenth  of  an  inch  outside  the  mark.  This  border  is  then 
thinned  with  a  corundum-wheel,  and  slit  as  seen  in  Fig.  194. 
The  collar  is  next  adjusted  on  the  natural  crown,  and  the  slit  bor- 
der bent  over  to  the  form  of  the  occluding  surface,  to  which  it  is 
burnished.  A  piece  of  pure  gold  plate,  about  iSTo.  30  gage,  is 
then  placed  on  the  occluding  surface  of  the  tooth  and  adapted  to 
it  and  to  the  collar.     The  gold  may  be  first  struck  in  the  form 


Fig.  195. 


Fig.  196. 


of  a  cap  on  a  block  of  lead,  hammering  into  it  a  die  of  the  surface 
of  the  tooth  to  be  crowned  (Fig.  195),  or  one  corresponding 
closely,  made  with  a  cusp  button  as  described  in  the  Hollingsworth 
System,  Part  III,  Chapter  XIV.  The  antagonizing  teeth  are  then 
occluded  on  the  gold,  which  is  thereby  pressed  to  form  to  articulate 
with  the  occluding  surfaces.  Enough  of  the  occluding  surface  of 
the  tooth  crowned  or  of  the  cusps  of  the  occluding  tooth  ought  to 
be  removed  to  allow  for  the  thickness  of  the  gold  covering  its 
surface.  The  collar  and  cap  are  next  removed  and  soldered.  This 
is  done  by  resting  the  collar  on  the  cap,  which  is  held  by  a  pair  of 
tweezers,  or  by  clamping  the  cap  and  collar  together  and  placing 
the  solder  in  small  pieces  around  the  collar  outside  the  cap,  at  A, 
Fig.  196,  and  soldering  by  holding  in  a  blue  gas  flame.     Only 


106  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

sufficient  solder  should  be  used  to  join  and  fill  the  seams,  so  that 
it  will  not  interfere  with  adjustment  on  the  natural  crown.  A 
closer  and  neater  joint  will  be  obtained  by  at  first  attaching  only 
one  corner  of  the  cap  to  the  collar,  with  the  smallest  possible 
quantity  of  solder,  then  readjusting  collar  and  cap  on  the  tooth, 
adapting  their  edges  together  with  a  foot-shaped  foil  condenser, 
and  then  completing  the  soldering. 

Method  No.  5. — When  intervening  space  will  permit  the  forma- 
tion of  a  solid  gold  occluding  surface  to  a  collar  crown,  the  follow- 
ing is  a  very  practical  method :  Fit  the  collar  and  trim  the  edge 
toward  the  occluding  surface  so  as  to  leave  between  it  and  the 
cusps  of  the  occluding  teeth  a  space  of  at  least  one-sixteenth  of  an 
inch.  Remove  the  collar,  and  solder  over  the  occluding  surface  a 
flat  piece  of  gold  plate  about  No.  30  gage  for  bicuspids,  or  platinum 
about  ~No.  34  for  molars,  preferably  using  a  small  quantity  of  hard- 
flowing  solder.  Trim  off  the  surplus  plate  flush  with  the  collar. 
To  form  the  cusps:  Melt  scraps  of  gold  plate  on  the  surface  of  a 
soldering-block  in  small  globules,  one  for  each  cusp,  and  slightly 
flatten  each  globule  on  an  anvil  with  a  hammer.  Place  the 
globules  on  the  surface  of  the  cap  in  proper  position  to  form  the 
cusps  and  attach  each  with  a  small  piece  of  hard-flowing  solder 
(Fig.  197).  When  all  the  cusps  are  attached,  then  melt 
on  sufficient  ordinary  solder  to  properly  fill  in  and  give 
form  to  the  surface  of  the  cap.  Adjust  the  cap  in  the 
mouth  and  trim  the  gold  of  the  occluding  surface  to  a 
form  which  will  permit  the  occlusion  of  the  other  teeth, 
then  polish  the  crown.  This  is  a  very  practical  and 
quick  method  of  forming  a  gold  crown. 
Method  No.  6. — The  methods  described  insure  a  perfect  occlu- 
sion of  the  crown  with  the  antagonizing  teeth.  In  the  absence  of 
antagonizing  teeth,  or  when  the  general  form  of  the  grinding-sur- 
face  permits  it,  the  cap  can  be  struck  up  With  a  die  similar  to  the 
one  shown  in  Fig.  195  that  approximates  in  size  and  form  what 
is  required.  The  cusps  are  then  filled  in  with  18-carat  gold  plate, 
hard-flowing  solder,  or  ordinary  solder,  and  the  edges  of  the  inner 
surface  of  the  cap  ground  level  on  the  side  of  a  corundum-wheel. 
The  entire  circumference  of  the  edge  of  the  collar  is  also  leveled, 
and  the  cap  adjusted,  clamped,  and  united.  If  the  cusps  of  the  cap 
are  filled  in  with  solder,  it  will  flow  down  and  join  the  collar  on 
the  inside;  if  with  gold  plate  or  hard-flowing  solder,  the  cap  and 
collar  must  be  joined  with  solder  either  on  the  inside  or  outside. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.      ^QT 


Method  No.  7. — When  the  mere  form  of  the  grinding-surface 
for  the  crown  is  all  that  is  required,  an  impromptu  one  may  be 
made  by  indenting  a  piece  of  pure  or  soft  gold  plate  with  the  round 
end  of  an  instrument-handle  on  a  piece  of  lead  to  form  the  cusps, 

Fig.  198. 


then  reversing  the  cap,  resting  it  on  a  flat  surface,  and  creasing  be- 
tween the  cusps  with  a  burnisher.  One  large  indentation,  such  as 
is  shown  in  Fig.  198,  A,  when  indented  and  creased  across  the 


Fig.  199. 


UPPER 


LOWER 


center  with  the  edge  of  a  flat,  thin  burnisher,  will  represent  a  bicus- 
pid. Four  indentations  closely  made,  as  shown  in  Fig.  198,  B, 
when  creased  between,  can  be  used  to  represent  an  upper  or  lower 

9 


108 


CROWN-,  BRIDGE-.  AXD  PORCELA.IX-WORK. 


molar,  and  three  similar  indentations,  properly  creased,  a  second 
or  third  upper  molar,  as  seen  in  Fig.  198,  C. 

Method  No.  8. — Metallic  caps,  or  forms  of  the  occluding  sur- 
faces of  teeth  for  use  in  constructing  crowns,  are  quickly  made 
with  a  die-plate,  such  as  is  shown  in  Fig.  199, *  v'in  which  are  four 
groups  of  intaglio  dies  representing  the  peculiar  cusps  of  the 
bicuspids  and  molars.  The  hubs  A,  B  (Fig.  200)  are  of  the  sizes 
shown,  and  are  made  of  an  alloy  composed  of  tin  one  part,  lead 


Fig.  200. 


four  parts,  melted  together.     The  mold  C  should  be  warmed,  the 

metal  alloy  poured  in  every  hole,  and  the  overflow  wiped  off 

■just  before  the   metal   stiffens; 
Fig   201  .         . 

this  will  make  the  butts  of  the 

hubs  smooth  and  flat.  After  a 
minute  or  two  the  mold  may  be 
reversed,  the  hubs  shaken  out, 
and  the  casting  process  con- 
tinued until  a  considerable  num- 
ber of  hubs  shall  have  been 
made.  In  Fig.  201  a  molar  hub 
is  shown  in  place  on  a  piece  of 
.No.  32  gold  plate,  which  lies 
over  the  upper  right  first  molar  die.  A  succession  of  blows  on 
the  hub  with  a  four-pound  smooth-faced  hammer  will  drive  the 


Dental  Cosmos,  vol.  xxix,  page  482. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.      ^Q9 

plate  into  the  die,  and  at  the  same  time  spread  the  hub  metal  from 
the  die  center  to  its  circumference,  in  such  a  manner  that  the 
plate  will  be  perfectly  struck  up  with  the  least  possible  risk  of 
being  cracked.  The  flattened  hub  is  seen  in  Fig.  202,  which 
also  shows  at  D  the  obverse  of  the  struck-up  hub,  and  at  E  the 
cameo  of  the  struck-up  plate,  having  every  cusp  and  depression 
sharply  defined.  The  counter-die  plate  (Fig.  199)  is  made  of 
a  very  hard  cast  metal,  which  will  admit  of  the  striking-up  of 
many  crown  plates  by  the  means  described,  if  the  crown  plates 
be  not  too  thick  and  stiff.  Of  course,  they  should  be  annealed  be- 
fore they  are  placed  over  the  die.     If  a  cusp  or  fissure  should 

Fig.  202. 


Fig.  203. 


A 


chance  to  crack  in  hubbing,  a  small  piece  of  plate  may  be  struck 
up  over  the  fissure,  and  then  soldered  to  the  original  cap." 

The  methods  which  have  been  described  for  the  construction  of 
all-gold  bicuspid  and  molar  crowns  are  those  generally  adopted 
in  practice.     Of  others,  Dr.  J.  J.  E.  Patrick's  method1  consists 
of  first  forming  a  very  narrow  collar  and  telescoping  it 
with  a  seamless  cap  of  the  form  of  the  crown,  and  sol- 
dering along  the  line  of  the  cap  to  the  collar.     When 
the  upper  edge  of  the  collar  is  lapped  over  on  the 
grinding-surface,  as  shown  in  Fig.  203,  the  soldering 
can  be  done  through  the  aperture  A.2 

AIl=Gold  Crowns  for  the  Incisors  and  Cuspids — AVhen  the 
teeth  are  abraded  and  short,  with  flat  incisal  edges  (Fig.  204),  and 
the  all-gold  crown  required  is  to  correspond  in  form  or  be  only  a 
little  longer,  the  gold  collar,  after  being  fitted  to  the  tooth,  is  slit 

1Dr.  Patrick,  the  Dental  Cosmos  for  October,  1888,  page  706. 
-  Dr.  R.  H.  Adair's  method. 


110 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


on  the  palatal  or  lingual  side,  and  bent  and  burnished  to  it.  The 
collar  is  then  removed  and  the  seams  soldered  together.  This 
is  best  done  by  holding  the  collar  in  a  Bunsen  gas  flame,  with  the 
solder  placed  in  position  in  very  small  pieces,  and  only  sufficient 
in  quantity  to  join  the  seams.  The  collar  is  next  adjusted  to  the 
tooth,  and  the  gold  at  the  incisal  edge  trimmed  even.     A  flat, 

Fig.  204. 


Fig.  205. 


thick  piece  of  gold  plate  or  clasp-material  is  soldered  across  the 
incisal  edge  to  form  and  inclose  that  portion  of  the  crown. 

Fig.  204  represents  a  case  of  abrasion  of  the  lower  teeth,  to 
which  all-gold  crowns  have  been  applied  to  open  the  bite,  as  shown 
in  Fig.  205.  In  such  cases,  owing  to  the  attrition  of  the  occluding 
teeth,  the  cap  forming  the  occluding  surface  should  be  constructed 
of  heavy  gold  clasp-plate  and  solder.  An  artificial  plate  replaces 
the  upper  teeth. 


ALL-GOLD  COLLAR  CROWNS  CONSTRUCTED  IN  SECTIONS.       m 

AY  hen  the  gold  crown  required  is  of  the  normal  form,  the  collar 
when  properly  fitted  should  be  cut  away  at  the  palatal 
section,  as  shown  in  Fig.  206.     The  edge  of  the  gold  is 
then  chamfered,  and  bent  and  burnished  over  the  incisal 
edge  and  sides,  close  to  the  natural  tooth.     To  this  open 
section  is  next  adapted  a  flat  piece  of  gold  plate,  the 
collar  is  removed,  and  the  parts  are  soldered  together, 
using  very  little  solder.     Small  pieces  of  solder  or  solder  filings 
can  be  melted  in  the  interior  of  the  incisal  edge  to  increase  its 
thickness,  if  necessary. 

Another  method  is  to  select  a  porcelain  tooth  of  the  desired 
form  and  of  the  size  of  the  gold  crown,  and  use  it  as  a  model  to  cast 
an  intaglio  die.  The  die  is  made  by  placing  moldine  in  a  pill 
box,  smoothing  off  the  surface,  and  imbedding  half  of  the  porce- 
lain tooth  with  the  palatal  or  pin  side  down.  Xext  wind  paper 
around  the  box,  slightly  warm  the  porcelain  tooth,  and  pour  in 
fusible  metal.  On  separating  and  removing  the  porcelain  tooth 
from  the  fusible  metal,  you  have  an  intaglio  die  of  the  face  of  it. 
The  use  of  Dental  Lac  for  this  purpose  is  described  in  Part  V. 
On  this  intaglio  die  shape  a  piece  of  soft  gold  plate,  Xo.  p  .,0- 
30  to  32  gage,  to  the  form  of  the  labial  surface  of  the 
crown.  Remove,  bend,  and  burnish  the  metal  round  to 
the  form  of  the  sides  and  palatal  section  of  the  tooth. 
trim  the  meeting  edges,  and  solder  (Fig.  207). 1 

A  fusible-metal  die  of  the  prepared  form  of  the  natural  tooth 
is  a  material  aid  in  the  construction  of  any  of  these  styles  of  crown. 

In  pulpless  teeth  with  only  a  little  or  none  of  the  natural  crown 
remaining,  the  root  can  be  shaped  and  capped  as  for  a  collar  crown 
with  a  porcelain  front  (see  page  83)  with  a  post  in  the  root- 
canal,  and  a  gold  front  applied  instead  of  one  of  porcelain.  This 
is  done  by  shaping  or  stamping  the  form  of  the  labial  face  of 
the  tooth  required  in  gold  plate,  mounting  it  in  position  on  the 
cap  as  in  the  case  of  a  porcelain  front,  and  attaching  with  solder. 
The  concave  portion  at  the  palatal  side  of  the  gold  front  is  filled 
in  and  shaped  with  solder  at  the  same  time.2 

The  construction  of  an  all-gold  crown  for  an  incisor  or  cuspid 
is  most  easily  accomplished  by  the  seam^ss  method  described  in 
Chapter  VEX 

1  Dr.  J.  T.  Usher.  Dental  Cosmos,  vol.  xl. 

2  Dies  and  molds  to  shape  plate  for  these  purposes  can  now  be  found  in  the 
Hollingsworth  and  other  crown  outfits. 


CHAP  TEE    VIII. 


The  Gold  Seamless  Cap-Croavn  System. 

seamless  root-caps  for  crowns  with  porcelain  fronts— in- 
cisors, cuspids,  and  bicuspids  — impressions  and  dies — 
method  op  stamping  seamless  metal  caps— all-gold  seam- 
less bicuspids  and  molars— models,  dies,  and  method  of 
swaging — all-gold  seamless  incisors  and  cuspids. 

This  method  consists  in  the  use  of  a  gold  seamless  cap  for  the 
construction  of  the  required  root-cap  or  crown. 

Seamless  Root=Caps  for  Incisor,  Cuspid,  and  Bicuspid  Crowns 
with  Porcelain  Fronts. — Incisor,  cuspid,  and  bicuspid  crowns 
with  porcelain  fronts  are  constructed  by  this  method  as  follows: 
The  natural  crown  is  ground  down  to  within  about  one-eighth  of 
an  inch  of  the  gum  at  the  palatal  wall,  or  enough  to  clear  the 
antagonizing  teeth  when  occluded,  and  slanting  from  the  posterior 
edge  of  the  pulp-chamber  to  the  cervico-labial  edge  of  the  gum  and 
slightly  under  its  margin  if  it  is  desirable  to  conceal  the  joining  of 
the  crown  with  the  root.  The  sides  are  shaped  the  same  as  for  a 
collar  crown  (Fig.  208). 

Impressions  and  Dies. — A  die  of  the  end  of  the  root  is  next 

made.     For  this  purpose  an  impression  of  the  part  is  taken  with 

gutta-percha  on  the  end  of  a  piece  of  wood 

trimmed  to  the  proper  size,  or,  better  still,  by 

placing   a   thin   mixture   of  plaster   of  Paris 

to  which  a  little  potassium  sulfate  has  been 

added,  or  some  moldine,  in  a  tube  formed  of  a 

strip  of  copper  about  one  and  one-half  inches 

in   length   and   three-eighths   of   an   inch   in 

diameter,  cut  out  on  the  sides  to  the  depth  of 

half  an  inch,  with  the  flange  for  the  palatal 

side  shortened1   (Fig.  209).     The  impression 

thus  taken  will  be  confined  almost  entirely 

to   the   end  of  the  root  to  be   capped.      When  gutta-percha  is 

used,    it   is   cooled   and  dried   perfectly.      A    strip   of   paper   is 


Fig.  208. 


Fig.  209. 


1  See  Part  V,   Chapter  III,  which  describes   how  to  make 
soldering. 
112 


tube  without 


THE  GOLD  SEAMLESS  CAP-CROWN  SYSTEM. 


113 


tied  around  the  wood  or  tube,  and  a  die  cast  with  the  fusible 
metal.  The  cooling  is  hastened  by  immersion  in  a  glass  of 
water.  When  cool,  the  die  is  removed  from  the  mold,  and  the 
metal  is  trimmed,  with  file  and  chisel,  a  little  deeper  than  the  gum 
has  permitted  the  impression  of  the  root  to  be  taken,  and  without 
altering  the  form  of  the  end  of  the  root  (Fig.  210).  A  counter-die 
is  then  made  by  driving  a  punch  of  suitable  size  into  the  surface  of 
a  block  of  pure  lead,  into  which  with  a  few  blows  of  a  hammer  the 
die  is  forced. 

Methods  of  Stamping  Seamless  Crowns. — A  cap  of  pure  gold, 
or  preferably  of  platinum,  with  which  to  cover  the  root  is  first 


Fig.  210. 


Fig.  211. 


Fig.  213. 


Fig.  212. 


made.  This  can  be  formed  by  placing  a  piece  of  the  plate,  ~No.  30 
gage,  of  suitable  size  upon  a  block  of  lead,  and  with  an  oval-shaped 
punch  one-fourth  of  an  inch  in  diameter  gradually  driving  it  into 
the  lead  until  the  gold  has  assumed  the  shape  of  a  cap  about  an 
eighth  of  an  inch  in  depth  (A,  Fig.  210).  The  gold  should  be 
protected  from  the  lead  by  the  intervention  of  a  piece  of  thin  kid 
and  should  be  withdrawn  from  under  the  punch  and  annealed 
from  time  to  time  during  the  process,  otherwise,  as  in  all  such 
operations,  it  is  liable  to  be  cracked. 

Caps  of  metal  can  be  made  in  different  sizes  and  kept  on  hand 
for  use  in  this  and  other  styles  of  crown-work  by  means  of  a 
stamping  machine,  which  in  principle  is  such  as  is  used  by 
jewelers  for  forming  cap-shaped  pieces  of  gold,  and  in  factories 


114 


GROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


for  making  copper  cartridges.  The  gold  plate,  cut  into  circular 
pieces,  is  pressed  through  a  steel  die-plate,  with  punches  gaged 
to  the  holes;  at  each  punch  a  small  portion  of  the  gold  is  turned 
over,  thus  preventing  its  lapping  or  creasing.  Repeated  annealing 
of  the  metal  is  very  necessary  in  this  process.  A  properly  con- 
structed press  should  be  used  for  the  purpose,  such  as  is  illustrated 
in  Fig.  214,  instead  of  hammering  the  punches  through  the  plates, 
because  when  treated  in  that  manner  the  metal  is  liable  to  be  torn 
or  creased. 

The  cap  is  then  annealed  and  swaged  on  the  die  to  the  form 


Fig.  214 


The  form  of  stamping  machine  introduced  by  the  late  Dr.  J.  J.  K.  Patrick. 

of  the  end  of  the  root  (B,  Fig.  210).  The  palatal  portion  of  the 
cap  should  be  allowed  to  go  well  up  under  the  free  edge  of  the 
gum,  and  at  the  cervico-labial  edge  it  can  be,  if  preferred,  cut 
out  to  the  edge  of  the  root.  In  the  process  of  adjustment,  the 
edges  which  fit  under  the  gum  should  be  marked  and  trimmed  as 
directed  in  describing  the  construction  of  a  collar  crown,  and 
then  burnished  close  to  the  sides  of  the  root  and  into  the  orifice 
of  the  root-canal,  forming  a  perfect-fitting  seamless  cap  (Fig. 
211).     A  platinum  pin  is  then  fitted  in  the  root-canal  and  soldered 


THE  GOLD  SEAMLESS  CAP-CROWX  SYSTEM.  115 

to  the  cap  (Fig.  212),  as  in  the  construction  of  the  gold  collar 
crown  with  porcelain  front  (page  86),  with  which  operation  the  re- 
mainder of  the  process  of  construction  is  identical.  Fig.  213  repre- 
sents the  completed  crown. 

The  advantages  of  this  style  of  crown  are,  simplicity,  as  the 
formation  of  a  collar  is  avoided,  and  strength,  as  a  large  portion 
of  the  natural  crown  can  be  left  at  the  palatal  side.  This  affords 
a  stronger  and  more  reliable  foundation  than  can  be  obtained  at 
any  other  point,  as  the  direction  of  the  force  in  mastication  is 
forward  at  an  angle  with  the  line  of  the  root,  and  although  the 
metal  of  the  cap,  where  it  encircles  the  root  at  the  cervico-labial 
edge,  is  entirely  removed,  the  crown  is  still  held  securely. 

AlUGoId  Seamless  Bicuspids  and  Molars. — All-gold  seamless 
crowns  for  bicuspids  and  molars  that  will  accurately  fit  the  natura  ( 
crown  and  root,  and  occlude  properly  with  the  antagonizing  teeth, 
are  easily  and  quickly  formed,  if  sufficient  of  the  natural  crown 
remains  to  admit  of  temporary  restoration  of  its  contour  with 
gutta-percha  or  any  other  suitable  plastic  material.  The  sides  of 
the  natural  tooth  and  the  occluding  surface  should  be  removed  at 
least  the  thickness  of  the  plate  to  be  used. 

Models,  Dies, and  Method  of  Swaging. — An  impression  of  the 
restored  tooth  is  next  taken  in  plaster  or  moldine  in  a  thin  copper 
tube  which  will  fit  under  the  free  margin  of  the  gum  and  closely 
encircle  the  tooth,  as  explained  on  page  112,  and  in  Part  V,  Chap- 
ter III,  which  also  explains  the  construction  of  the  copper  tube. 
A  die  is  then  formed  of  fusible  alloy;  or  a  plaster  model  can  be 
made  from  an  impression  of  the  tooth  taken  in  wax,  and  a  mold 
obtained  from  the  model  with  moldine.  Additional  preparation 
and  shaping  of  the  natural  crown  to  receive  the  artificial  crown 
can  then  be  proceeded  with. 

Where  the  natural  crown  is  very  badly  decayed  or  broken 
down  and  the  method  just  described  is  not  practicable,  the  por- 
tion of  the  natural  crown  or  root  remaining  should  be  shaped 
and  prepared  to  receive  an  artificial  crown.  Then  the  form  of 
the  cervix  is  ascertained  with  a  wire,  as  described  on  page  78, 
an  impression  of  the  parts  taken  in  wax  or  impression-compound, 
and  the  wire  form,  the  twisted  ends  having  been  shortened,  is 
carefully  adjusted  on  the  wax  at  the  cervical  line.  The  plaster 
model,  when  made,  will  show  the  wire  slightly  imbedded  in  the 
plaster.     The  plaster  should  be  trimmed  to  the  inner  edge  of  the 


116 


CROWN-,  BRIDGE-,  AND  PORCELAIN AYORK. 


wire,  as  that  represents  the  exact  form  of  the  root  (Fig.  215),  and 
the  wire  cut  and  removed. 

Another  method  is  to  fit  a  copper  collar  accurately  to  the  root 
with  projecting  points  on  the  sides  of  the  collar,  which  will  remove 
in  the  impression.  In  such  a  case  plaster  must  be  used  for  the 
impression.  When  the  model  is  made  the  collar,  on  being  cut  and 
removed,  will  represent  the  exact  form  of  the  neck. 

From  a  "bite"  taken  in  wax  and  fitted  on  the  model  a  plaster 
articulation  is  then  made.  A  hole  is  drilled  in  the  center  of  the 
form  of  the  root  on  the  model  to  be  crowned.  In  this  hole,  and 
over  the  end  of  the  root,  a  ball  of  soft  plaster,  slightly  colored  with 
carmine,  is  placed,  and  the  teeth  of  the  articulation,  covered  with 
tin  foil,  closed  on  it.  This,  on  separation,  gives  the  outline  of  the 
form  of  the  grinding-surface  for  the  crown.     The  sides  of  the 


Fig.  215. 


Fig.  216. 


plaster  are  then  trimmed  to  the  form  of  the  crown,  and  the  whole 
carved  in  detail  (Fig.  216).  As  the  crown  will  always  stamp 
larger  in  circumference  than  the  die,  in  proportion  to  the  thick- 
ness of  the  gold  used,  it  should  be  remembered  allowance  must  be 
made  by  trimming  off  a  proportionate  amount  of  the  grinding- 
surface,  either  before  the  impression  of  the  natural  tooth  is  taken, 
or,  from  the  plaster  model  of  the  tooth  when  it  is  shaped.  The 
former  is  the  preferable  method  to  practice,  as  the  latter  will  after- 
ward require  the  removal  of  at  least  the  same  proportionate 
amount  from  the  natural  tooth  when  the  crown  is  fitted,  which  is 
not  always  easily  done. 

When  the  plaster  model  for  the  crown  is  made,  it  is  separated 
from  the  rest  of  the  model  at  the  dotted  line  seen  in  Fig.  216,  and 
trimmed  in  the  form  shown  by  the  cast  A,  Fig.  217.  From  this 
model  the  die  is  made  in  a  tube  with  moldine  and  fusible  metal,  as 


TEE  GOLD  SEAMLESS  CAP-CROW^  SYSTEM. 


117 


already  described,  and  in  Part  V,  Chapter  III.  The  cast  should 
always  be  lengthened  at  the  neck,  so  that  the  crown  when  con- 
structed shall  have  a  surplus  in  depth  of  gold  to  allow  for  any 
trimming  or  shaping  of  the  collar  that  may  be  required.  The 
counter-die  (B,  Fig.  217)  is  made  by  punching  a  hole  in  a  block 
of  lead  and  hammering  the  die  into  it.  The  crown,  which  is  usu- 
ally formed  of  gold  only  slightly  alloyed,  or  gold  lined  with 
very  thin  platinum  from  Xo.  29  to  No.  32  gage,  is  then  made  by 
first  stamping  a  piece  of  plate  (see  page  114)  in  the  form  of  a  cap  of 


Fig.  217. 


Fig.  218. 


Fig.  219. 


gold  (A,  Fig.  218),  which  is  then  placed  on  the 
cast,  tapped  with  a  horn  hammer  to  the  general 
shape,  and  with  the  aid  of  the  counter-die  (B,  Fig.  217)  swaged  to 
the  form  of  the  crown  B,  Fig.  218.  A  piece  of  kid-leather  or 
rubber-dam  should  be  used  to  cover  and  protect  the  gold  from  the 
lead,  and  to  facilitate  its  removal  from  the  counter-die.  An  allow- 
ance for  the  thickness  of  the  gold  must  be  first  made,  by  driving 
the  die  with  two  thicknesses  of  kid,  without  the  gold  on  the  cast, 
into  the  counter-die  to  enlarge  it.  If  this  is  not  done,  the  gold  is 
liable  to  be  torn  in  the  swaging. 

AU=GoId  Incisors  and  Cuspids. — Incisor  and  cuspid  crowns 
from  which  a  portion  of  the  gold  on  the  labial  aspect  is  to  be  re- 
moved (see  article  on  "Shell  Anchorage,"  page  210),  or  which  are 
to  be  used  entire  as  supports  for  bridge-work,  can  usually  be  ad- 
vantageously formed  with  seamless  caps  (Fig.  219).  The  necks 
of  these  crowns  will  usually  have  to  be  contracted  in  fitting  in  a 
contracting  plate,  or  slit,  lapped,  and  soldered. 


CHAPTER    IX. 

Imparting  Contour  to  Seamless  Gold  Crowns. 

crowns  swaged  on  dies— method  of  slitting  and  contracting 
the  neck — use  of  contouring  pliers— external  application 
of  metal— to  contour  on  the  die  with  a  swager — sectional 
mold  method— formation— molds— shaping  the  cap— ready- 
made  gold  crowns. 

Crowns  Swaged  on  Dies. 

Method  of  Slitting  and  Contracting  the  Neck. — Crowns  for 
cases  in  which  decay  has  extensively  involved  the  approximal  sides, 
owing  to  encroachment  of  the  adjoining  teeth,  generally  require 
very  little  if  any  contour.  Some  form  can  be  imparted  to  a  straight- 
sided  seamless  crown  by  slitting  the  collar  directly  in  the  center  of 
the  palatal  side,  contracting  the  neck,  tapering  the  nnderlapping 
portion,  adjusting  on  the  tooth,  burnishing  the  gold,  removing, 
and  soldering.  This  contraction  also  imparts  a  very  close  fit  to  the 
collar.  When  considerable  contour  is  required,  the  crown  should 
lie  formed  with  the  desired  size  and  shape  of  grinding-surface. 
The  collar  is  then  to  be  slit  and  contracted  at  one  or  each  of  the 
approximal  sides  as  is  found  necessary,  fitted,  and  soldered. 

Use  of  Contouring  Pliers. — "Contouring"  pliers  are  used  by 
some  to  give  form  to  a  seamless  crown,  sufficient  to  knuckle  it 
against  the  adjoining  teeth ;  but  the  bulge  that  is  imparted  by  this 
means  is  generally  located  well  toward  the  neck  of  the  crown, 
instead  of  being  close  to  the  grinding-surface  where  it  is  required. 

External  Application  of  Contour — A  close  knuckling  of  the 
grinding-surface  of  a  seamless  crown  to  that  of  an  adjoining  tooth 
can  always  be  easily  made  by  scratching  the  surface  of  the  gold  at 
the  point  the  knuckling  is  desired,  packing  on  Moss  Fibre  Gold  or 
foil,  and  flowing  a  little  solder  over  it,  then  fitting  and  trimming 
to  the  desired  size  and  shape. 

To  Contour  on  the  Die  with  a  Swager. — A  seamless  crown 
may  be  given  contour  on  the  swaging  die  in  the  following  manner: 
118 


IMPARTIXG  COX  TOUR  TO  SEAMLESS  GOLD  CROWNS. 


119 


Fir,.  221). 


Form  the  die  for  the  intended  crown  of  a  fusible  metal  which  melts 
at  180°  F.  Reduce  the  neck  of  the  die  to  the  shape  and  size  re- 
quired for  the  crown,  which  can  be  accurately  determined  by 
measurement  with  a  stripof  copper, or, cast  a  die  of  the  exact  shape 
from  a  sectional  plaster  mold  of  the  tooth,  formed  longitudinally 
in  halves.  Place  over  the  die  a  tight-fitting  seamless  gold  cap. 
Mallet  and  burnish  the  gold  as  closely  as  possible  to  the  die.  If 
it  is  a  bicuspid  or  molar,  swage  the  grinding-surface.  Place  the 
crown  in  a  small  shot  swage,  as  illustrated  in 
Fig.  220,  surrounded  with  the  shot,  and  insert 
and  hammer  the  plunger,  which  will  cause 
the  shot  to  uniformly  swage  the  gold  by  de- 
grees closely  to  the  die.  When  the  swaging 
is  completed,  remove  the  die  from  the  crown 
by  placing  it  in  holing  water  to  melt  out  the 
fusible  metal.  Should  any  of  the  metal  ad- 
here to  the  gold,  immerse  the  crown  in  nitric 
acid,  which  will  quickly  dissolve  it. 

Sectional  Mold  Method. — The  artistic  re- 
quirement of  all  gold  crown-work  is,  that  it 
shall  reproduce  the  anatomical  contour  of  the 
natural  teeth.  Such  a  form  can  be  given  bi- 
cuspids and  molars  by  the  sectional  mold 
method  more  easily  than  by  any  other.  For 
this  reason  it  is  the  method  adopted  for  the 
manufacture  of  ready-made  gold  seamless  con- 
tour crowns.  The  sectional  mold  method,  though  a  practical  one 
for  the  manufacturer,   will   be  generally  found  tedious  for  the 


Fig.  221. 


Fig.  222. 


Fig.  223. 


feJJI 

;   i 
ifill 

i 

formation  of  a  single  crown  for  an  individual  case  in  the  hands  of 
the  ordinary  practitioner. 

Formation. — To  describe  and  illustrate  the  process  we  will  take 


120 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK 


a  superior  molar  (Fig.  22 1).  A  natural  tooth,  or  one  made  of 
plaster,  is  used  as  a  model.  From  this  a  sectional  mold  is  made  in 
Babbitt's  metal,  zinc,  or  fusible  alloy,  as  illustrated  in  Figs.  222 
and  223. 

Molds. — Flasks  are  now  manufactured  and  sold  to  facilitate  the 
formation   of   a   metallic   sectional   mold.      Fig.    224    illustrates 

Fig.  224. 


a  flask  of  this  kind,  "the  Turner."  The  form  of  the  tooth  to 
be  molded  is  placed  in  the  center,  occluding  surface  up.  The 
molding  ring  is  set  around  the  tooth  form  (small  diameter  up)  and 


Fig.  225. 


the  two  metal  strips  placed  inside  the  molding  ring  on  each  side  of 
the  tooth  form,  but  not  touching  it,  on  a  straight  line  from  mesial 
to  distal  side.  The  melted  fusible  metal  is  next  poured,  covering 
the  tooth  form  and  forming  the  entire  mold.  The  larger  molding 
ring  is  placed  around  the  smaller  one  to  cool  the  metal.  While 
the  metal  is  yet  slightly  warm  the  metallic  mold  is  taken  out  of  the 


IMPARTING  CONTOUR  TO  SEAMLESS  GOLD  CROWNS.        121 

ring,  the  strips  on  the  sides  removed,  and  the  mold  split  in  two 
through  the  slots  formed  by  the  metal  strips  with  the  dividers 
shown  in  Fig.  225.  The  tooth  form  is  next  removed,  the  parts 
put  together  the  same  as  before  being  split  and  set  back  in  the 
small  ring,  and  the  mold  is  then  complete. 

Shaping  the  Cap. — Into  the  mold  a  cap  of  gold  (Fig.  226)  28 
to  24  carats  fine,  ISTo.  28  to  30  gage,  is  adjusted,  fitting  tightly  the 
orifice  of  the  closed  mold.  The  mold  is  placed  in  a  vise,  the  cap 
expanded  to  the  general  form  of  the  mold  by  hammering  into  it 
a  mass  of  cotton  or  some  other  suitable  material,  and  with  a  wood 


Fig.  226. 


Fig.  227 


Fig.  22S. 


point  or  a  burnisher  revolved  by  the  dental  engine  burnished  into 
every  part  of  the  mold  (Fig..  227).  To  facilitate  the  process,  the 
mold  should  be  frequently  opened,  and  the  gold  annealed.  Fig. 
228  represents  the  completed  crown. 

Ready=Made  Gold  Crowns. — Ready-made  seamless  gold 
crowns,  such  as  the  "Evans,"  are  made  in  the  manner  above  de- 
scribed. They  are  arranged  in  sets  of  different  sizes,  representing 
the  average  forms  generally  required,  with  some  of  the  usual 
deviations. 


CHAPTER    X. 

Adjustment  of  Seamless  Gold  Crowns. 

expansion  of  the  collar  and  crown— alteration  of  a  side  oh 
part  of  a  crown— alteration  of  the  occluding  surface — 
contraction  of  the  neck— to  deepen  the  cusps — to  point, 
lengthen,  or  narrow  in  appearance  the  labial  cusp— to 
remove  the  indentation  between  cusps — strengthening 
and  reinforcement  of  seamless  gold  crowns— method  of 
forming  a  solid  grinding-surface — external  reinforce- 
ment of  seamless  gold  in  "close  bites" — comparative 
merits  of  the  sectional  and  seamless  methods  of  con- 
structing gold  crowns. 

A  superior  molar — one  of  the  most  difficult  teeth  to  operate  on 
— will  serve  as  a  typical  case  to  illustrate  the  process  of  adjustment. 
The  crown  or  root  is  first  shaped,  and,  if  necessary,  built  down  with 
amalgam,  straight,  or  tapering  slightly  on  its  sides  toward  the  oc- 
cluding surface,  as  described  at  page  40.  A  crown  of  the  proper 
size  is  specially  made  or  selected  from  a  ready-made  stock.  If  the 
latter,  its  selection  will  be  facilitated  by  having  a  plaster  model  of 
the  case  and  a  wire  measurement  of  the  neck.     The  croAvn  is  an- 


Fig.  229. 


Fig.  230. 

^  A 


Fig.  231. 


nealed,  slipped  over  the  end  of  the  root  or  tooth,  and  gently  worked 
upward — the  gold  of  the  collar  will  adapt  itself  to  the  form  of  the 
root  in  the  operation — until  the  edge  meets  the  margin  of  the  gum 
(A  A,  Fig.  229). 

1.  Mark  a  line  (B)  on  the  gold  parallel  with  the  margin  of 
the  gum. 

2.  Remove  and  trim  to  this  line  (A,  Fig.  230).  If  necessary, 
repeat  the  marking  and  trimming  until  the  edge  meets  the  gum 
evenly. 

3.  Bevel  the  edge  of  the  gold,  readjust  the  crown  and  press 
122 


ADJUSTMEXT  OF  SEAMLESS  HOLD  C'A'OU  .V.S. 


123 


it  up  until  the  edge  of  the  collar  passes  under  the  margin  of  the 
gum,  and,  if  the  occlusion  is  correct,  burnish  the  gold  to  the 
cervix  (Fig.  231). 

Expansion  of  the  Collar  and  Crown. — If  the  collar  of  the 
crown  needs  enlargement,  it  is  easily  and  most  properly  accom- 
plished with  crown  expanders  (shown  in  miniature  form  in  Fig. 
232),  the  points  of  which  should  he  introduced  at  first  just  within 
the  edge  of  the  neck,  and  the  gold  spread  sufficiently  to  allow  it  to 
fit  over  the  end  of  the  natural  crown  or  root,  the  process  of  ex- 
pansion being  gradually  continued  as  the  crown  is  brought  into 
position.  By  proceeding  in  this  manner  too  great  expansion  is 
avoided. 

Fig.  232.  Fig.  233. 


Alteration  of  a  Side  or  Part  of  a  Crown. — The  contour  of  one 
or  both  sides  can  be  depressed  and  the  crown  thus  narrowed  by 
introducing  the  points  of  a  crown  expander  or  some  tool  that  will 
fit  loosely  inside  the  crown,  then  steadying  the  crown  with  the 
fingers  as  shown  in  Fig.  234,  and  tapping  the  sides  to  be  reduced 
with  the  flat  end  of  a  riveting  hammer.  Pliers  will  also  accom- 
plish it,  one  beak  being  placed  inside  of  the  crown,  and  the  other 
against  the  bulge  on  the  outside  (Fig.  233).  This  is  necessary 
when  the  side  of  a  crown  presses  on  an  adjoining  tooth,  and  the 
crown  is  thus  prevented  from  coming  into  proper  position. 

To  Alter  the  Shape  of  a  Portion  of  the  Collar  or  Side  of  a 
Crown,  slip  the  crown  over  the  point  of  an  anvil,  or  the  end  of  a 
pair  of  expanders,  or  a  small  round-handled  instrument  held  in  a 

10 


124 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


vise,  and  then  tap  the  part  to  be  altered  with  the  flat  end  of  a 
riveting  hammer  to  the  form  desired. 

Alteration  of  the  Occluding  Surface — Before  the  crown  is 
pressed  up  to  its  apparently  proper  position,  the  occlusion  should 
be  examined,  and  calculations  carefully  made  to  obviate  any  de- 
fects of  articulation,  which  can  be  readily  corrected  at  this  stage  by 
proper  manipulation  of  the  crown. 


Fig.  234. 


Fig.  235. 


Fig.  236. 


Alteration  of  the  Grinding=Surface — Place  crown  in  position 
on  the  tooth  and  flatten  the  part  with  a  large  gold-foil  condenser 
tapped  with  the  mallet,  or  hold  the  crown  and  tap  the  part  as 
shown  in  Fig.  235.  The  closing  of  the  antagonizing  teeth  upon 
the  crown  by  the  patient  with  force  will  aid  or  complete  the 
operation  of  articulating. 

Contraction  of  the  Neck — -To  slightly  contract  the  neck  bend 
in  the  edge  of  the  gold  at  the  neck  with  narrow-beaked  pliers, 
and  holding  the  crown  evenly  and  firmly  between  the  fingers, 

as  shown  in  Fig.  236,  burnish  the  sides 
and  neck  section  inward  around  the  entire 
circumference  of  the  crown. 

To  Considerably  Contract  a  Crown. — 
Slit  the  gold  longitudinally  at  the  palatal 
or  lingual  side  its  full  length  to  the  grind- 
ing-surface,  as  shown  in  Fig.  237,  bevel 
off  the  edge  to  lap  under, 
contract  the  crown,  read- 
just to  the  tooth,  remove, 
place  the  smallest  quantity 
of  solder  or  dampened  flux 
solder  filings  in  position  on  the  seam,  and  then  solder  by  holding 


Fig.  237. 


ADJUSTMENT  OF  SEAMLESS  GOLD  CROWNS. 


125 


in  an  alcohol  flame,  or  by  carefully  heating  in  the  upper  section 
of  a  Bunsen  flame.  Xext  proceed  with  the  further  adjustment  of 
the  crown. 

The  line  of  the  seam  can  be  stoned  off  and  polished  after  the 
crown  has  been  fitted,  and  additionally  soldered  to  strengthen  the 
sides  or  grinding-surface. 

To  Deepen  the  Cusps.- — Trim  a  piece  of  wood  to  the  form 
shown  in  Fig.  238,  rest  the  neck  on  a  folded  napkin,  and  press  th" 
wood  between  the  cusps. 

To  Point,  Lengthen,  or  Narrow  in  Appearance  the  Labial 
Cusp  of  an  upper  bicuspid  crown,  gently  tap  the  gold  on  each  side 
of  the  labial  cusp  toward  the  point  at  the  angle  shown  in  Fig.  239. 

To  Remove  the  Indentation  between  the  Cusps  and  thus 
flatten  the  entire  grinding-surface,  introduce  inside  The  crown  a 


Fig.  238. 


Fig.  239. 


Fig.  240. 


flat-ended  piece  of  wood  the  size  of  the  crown  and  press  downward 
as  shown  in  Fig.  240. 

Strengthening  and  Reinforcement  of  Seamless  Gold  Contour 
Crowns. — Additional  strength  and  stiffness  can  be  given  to  seam- 
less gold  crowns,  when  desired,  in  several  ways,  by  soldering  in 
an  open  flame.  The  liability  of  melting  the  gold  which  forms  the 
side  of  the  crown  in  the  operation  has,  with  some,  been  one  of  the 
objections  to  their  use.  Great  care  must  be  exercised  to  avoid 
this,  to  which  end  the  crown  should  be  held  in  the  upper  sec- 
tion of  the  flame,  watched,  and  instantly  removed  as  soon  as  the 
solder  fuses  and  flows.  The  heat  should  be  very  gradually  and 
uniformly  applied  by  twisting  and  moving  the  crown  well  up  and 
down  in  the  flame,  so  that  the  gold  of  the  crown  shall  at  no  time 
become  hotter  than  the  solder.  If  this  precaution  is  not  observed 
the  solder  is  apt  to  penetrate  the  gold  of  the  crown.  The  crown 
should  be  held  in  such  a  position  that  a  full  view  of  the  interior  is 


126  GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

presented  and  the  melting  of  the  solder  rendered  visible;  this  will 
occur  at  a  red  heat. 

To  stiffen  the  whole  interior  of  the  crown,  after  it  has  been 
properly  adjusted,  dampen  the  inner  surface  with  wet  cotton  on 
the  j)oint  of  an  instrument;  place  in  the  interior  a  quantity  of 
fluxed  solder  filings  (solder  filings  mixed  with  Parr's  flux  or  pul- 
verized vitrified  borax) ;  place  the  finger  over  the  neck  end  of  the 
crown,  invert,  and  shake  well.  A  portion  of  the  solder  filings 
will  adhere  evenly  all  over  the  wet  surface.  The  finger  is  then 
removed  and  the  surplus  dropped  back  into  the  bottle.  Catch  the 
edge  of  the  neck  with  tweezers,  and  heat  the  crown  in  a  large 
alcohol  or  gas  flame  until  the  solder  fuses,  when  it  will  flow  evenly 
over  the  surface  of  the  gold  without  materially  altering  the  general 
form. 

A  crown  may  be  stiff 'ened  externally  by  flowing  a  film  of  22-carat 
coin  solder  over  all  or  part  of  its  surface. 

The  grinding-surface  of  seamless  crowns  can  be  thickened  by 
filling  the  interior  of  the  cusps  with  solder.  If  considerable  of  the 
natural  crown  is  present,  the  solder  should  be  confined  to  the  cusps, 
avoiding  all  excess,  which  would  be  liable  to  obstruct  the  read- 
justment of  the  crowns,  a  difficulty  which  often  occurs  and  which 
is  troublesome  to  correct. 

Method  of  Forming  a  Solid  Gold  Grinding=Surface  with 
Moss  Fibre  Gold  and  Solder. — A  grinding-surface  of  solid  gold, 
which  will  be  uniform  in  shape  to  that  of  the  natural  crown  it  is 
to  cap  and  not  liable  to  interfere  with  the  readjustment,  may  be 
formed  as  follows :  Dry  the  gold  crown  and  place  in  the  interior 
of  the  grinding-surface  a  layer  of  Moss  Fibre  Gold.  Insert  the 
crown,  press  to  position  and  occlude  the  teeth,  and  remove  the 
crown.  The  Moss  Fibre  Gold  will  exhibit  an  impression  of  the 
tooth.  Add  more  Moss  Fibre  Gold  until  a.  nearly  condensed  lining 
of  it  fills  the  grinding-surface.  ISText  saturate  this  lining  of  the 
Moss  Fibre  Gold  with  solder.  This  is  done  by  applying  and  fusing 
the  solder  cut  in  very  small  pieces,  or  fluxed  solder  filings,  on  the 
surface  of  the  gold,  a  very  little  at  a  time  and  in  quantity  only 
so  much  as  the  Moss  Fibre  will  absorb.  If  more  solder  than  this 
is  applied  the  adjustment  of  the  crown  is  liable  to  be  obstructed. 
If  the  operation  is  properly  performed  it  will  result  in  an  interior 
of  gold  that  will  correspond  in  form  with  that  of  the  natural 
tooth. 


ADJUSTMENT  OF  SEAMLESS  COLD  CROWNS.  ^97 

External  Reinforcement  with  Platinum  and  Gold  in  "Close 
Bites." — In  a  very  close  Lite  when  removal  of  only  very  little  of 
the  occluding  surface  of  the  tooth  crowned,  or  of  the  occluding 
teeth,  is  for  any  reason  permissible,  a  film  of  solder  or  18-carax 
plate  may  be  flowed  over  the  outer  surface,  or  a  piece  of  perforated 
platinum  foil  of  a  size  only  sufficient  to  cover  the  occluding  sur- 
face can  be  pressed  or  swaged  to  its  form  and  closely  soldered,  using 
only  a  very  small  quantity  of  solder.  By  this  latter  method  the 
grinding-surface  will  ocupy  the  least  possible  space  and  present  a 
metallic  face  which  will  very  effectually  resist  attrition.  The 
platinum  will  absorb  enough  of  the  solder,  if  sufficient  heat  is 
applied,  to  give  the  grinding-surface  of  the  crown  a  color  resem- 
bling that  of  clasp-gold. 

Gold  seamless  crowns,  especially  those  made  of  platinized 
gold,  can  be  filled  solid,  by  investing  the  outside  surface  in  plaster 
and  marble-dust,  heating  up  the  investment,  placing  solder,  small 
pieces  at  a  time,  inside  the  crown  and  fusing  it,  by  applying  the 
full  flame  of  the  blowpipe  around  or  underneath  the  investment. 

Seamless  crowns  can  1  e  inserted  in  an  easy  and  inexpensive 
manner  by  filling  in  the  lower  section  of  the  crown  with  amalgam 
from  which  the  mercury  has  been  well  pressed  out  instead  of  gold, 
and  then  cementing  on  the  crown  with  oxyphosphate  in  the  usual 
manner.  In  a  case  so  inserted,  with  no  antagonizing  teeth,  the 
result  is  the  same  as  though  the  inside  of  the  occluding  surface  of 
the  crown  was  filled  with  gold;  but  if  antagonizing  teeth  are 
present,  the  gold  of  the  crown  is  liable  to  wear  through  in  places 
and  expose  the  amalgam. 

Altering  a  Gold  Crown  to  the  Exact  Form  of  Any  Corre= 
sponding  Natural  Tooth. — Keady-made  gold  seamless  contour 
crowns  frequently  afford  the  means  of  easily  and  quickly  perform- 
ing a  crowning  operation.  In  a  case  having  nearly  all  the  natural 
teeth  present,  in  which  the  occluding  surface  and  sides  differ  in 
shape  from  the  form  of  the  gold  crown,  to  such  an  extent  as  to 
interfere  writh  its  adjustment,  a  die  of  the  natural  crown  should 
be  made  of  fusible  metal  (Melotte's  Fusible  Alloy,  see  Part  V. 
Ohapter  III),  and  with  it  the  interior  of  the  gold  crown  should 
be  altered  in  shape  sufficiently  to  receive  the  natural  crown, 
I>y  resting  the  occluding  surface  of  the  gold  crown  on  a  folded 
napkin  and  gently  tapping  the  die  into  it.  By  this  means  a  ready- 
made  gold  crown  is  quickly  altered  to  the  exact  shape  of  any  tooth. 


128  CROKX-,  BRIDGE-,  AXD  PORCELAIN-WORK. 

Comparative  Merits  of  the  Seamless  and  Sectional  Methods 
of  Constructing  Gold  Crowns. — The  seamless  and  sectional 
crown  methods  each  possess  their  respective  advantages  for  the 
accomplishment  of  the  work  in  hand.  By  expertness  the  same 
effectiveness  in  result  can  generally  be  accomplished  by  either 
method.  The  constructive  details  of  each  adapt  it  specially  to 
certain  classes  of  work,  wherein  for  this  reason  it  is  superior 
to  the  other  in  that  it  affords  facilities  for  the  accomplish- 
ment of  the  result  with  less  labor.  Thus,  crowns  for  very  short 
teeth  of  abnormal  occlusion,  also  cases  of  abrasion  requiring 
special  forms  of  incisal  and  occlusal  surfaces  of  solid  metal,  are 
generally  best  constructed  in  sections.  Bicuspids  and  molars  as 
well  as  incisors  and  cuspids,  when  all  or  nearly  all  of  the  natural 
tooth  is  present  and  the  occlusion  is  normal,  are  generally  con- 
structed to  advantage  by  the  seamless  methods. 


CHAPTEK    XL 

Various  Forms  of  Gold  Crowns  with  Porcelain  Fronts. 

porcelain  and  gold  crown  without  a  collar— roots  below  gum- 
margin:  special  forms— cup-shaped  cap:  dr.  van  woert's 
method— dr.  chupein's  method — ready-made  post  and  disk— 
dr.  sanger's  method— double  cap-crown. 

Porcelain  and  Gold  Crown  without  a  Collar. — The  root  of  a 
cuspid  will  be  taken  as  a  typical  case  to  illustrate  the  construction 
of  this  style  of  crown. 

The  end  of  the  root  is  prepared  the  same  as  for  a  porcelain 
crown  (Fig.  241).  The  root-canal  is  enlarged  with  a  drill  which 
will  closely  fit  the  opening  and  the  orifice  slightly  reamed.  Into 
the  canal,  gaging  its  full  diameter,  is  fitted  a  piece  of  iridio- 


Fig.  241. 


Fig.  242. 


Fig.  243. 


Fig.  244. 


platinum  wire,  tapered  off  to  a  point,  so  that  by  introducing  it 
far  up  the  canal  greater  strength  can  be  obtained,  and  the  root 
rendered  less  liable  to  longitudinal  fracture  from  pressure  in 
a  forward  direction.  A  piece  of  platinum  plate,  a  trifle  larger 
than  the  end  of  the  root,  of  about  No.  34  gage,  with  a  hole 
punched  in  its  center,  is  then  slipped  on  the  post,  which  it  must 
fit  tightly  (Fig.  242). 

When  the  post  is  adjusted  firmly  in  the  canal,  the  platinum 
plate  is  pressed  down  on  the  root,  and  burnished  into  the  orifice 
of  the  canal  around  the  post.     When  the  post  is  withdrawn  from 

129 


130  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK . 

the  root,  the  platinum  will  adhere  to  it,  if  fitted  closely,  with- 
out the  use  of  wax.  A  particle  of  pure  gold  with  borax  is  put  in 
the  joint,  and  melted  in  a  Bunsen  gas  flame.  Barely  enough 
of  the  gold  should  be  used  to  unite  the  parts.  When  soldered, 
the  post  and  cap  are  again  adjusted  in  the  mouth  and  the  cap 
malleted  and  burnished  to  the  form  of  the  end  of  the  root,  so  that 
its  edge  will  leave  a  mark  on  the  platinum.  The  cap,  on  being 
removed,  should  be  trimmed  to  this  mark,  and  again  burnished  on 
the  root  (Fig.  243).  Sometimes  the  platinum  may  be  slightly 
burnished  over  the  edge  around  the  palatal  portion  of  the  root. 
The  post  is  then  cut  off  just  above  the  platinum,  and  a  plate  tooth 
fitted,  backed,  and  cemented  with  wax  in  position  on  the  cap,  as 
described  on  page  88.  The  whole  is  then  removed,  invested,  and 
soldered  with  gold,  which  should  be  melted  in  at  the  base  of  the 
post,  as  at  this  point,  when  in  use,  the  strain  is  very  great.  The 
post  is  then  barbed,  and  the  crown  is  cemented  to  the  root  with 
gutta-percha,  os:yphosphate  cement,  or  both  combined  (Fig.  244). 

Roots  Below  Gum=Margin. — The  crown  just  described  is  a 
suitable  form  for  application  in  cases  where  the  cervical  end  of  the 
root  through  either  decay  or  fracture  is  considerably  below  the 
surface  of  the  gum  and  does  not  admit  of  the  use  of  a  collar.  In 
such  cases  the  end  of  the  root  should  be  first  fully  exposed  by  pellets 
of  gutta-percha  fastened  in  the  orifice  of  the  root-canal  and  extend- 
ing over  the  surface  of  the  end  of  the  root,  pressing  away  the  gum, 
the  application  being  repeated  as  often  as  necessary.  The  above 
method  of  shaping  the  cap  is  preferable  to  stamping  it,  as  sug- 
gested by  some  writers. 

Special  Forms. — Several  methods  of  capping  are  practiced  in 
which,  by  giving  the  end  and  sides  of  the  root  specified  forms,  the 
use  of  a  collar  is  avoided  and  protection  against  decay  or  fracture 
is  promised. 

Cup=Shaped  Cap.1 — The  root  is  removed  to,  or  very  nearly  to  the 
line  of  the  gum,  and  the  edge  of  the  end  rounded  off  under  the 
gum-margin,  leaving  the  end  tapering  to  the  orifice  of  the  canal, 
as  illustrated  in  Fig.  245.  The  cap  is  made  of  a  disk  of  gold,  about 
No.  31  or  32,  or  of  platinum,  about  No.  34  gage.  This  is  first 
perforated  and  adapted  to  the  orifice  of  the  root-canal,  which  re- 
quires to  be  slightly  enlarged.     The  disk  is  then  slit  at  the  center 

1  Dr.  J.  Rollo  Knapp's  method. 


FORMS  OF  GOLD  CROWNS  WITH  PORCELAIN  FRONTS.       131 

of  the  palatal  side  and  slightly  lapped  (A,  Fig.  246),  and  then 
again  fitted  to  the  end  of  the  root  and  closely  adapted  to  its  surface 
and  margin,  which  the  lapping  over  of  the  slit  easily  permits.  The 
edges  are  then  united  with  the  least  possible  quantity  of  solder. 
The  edges  of  the  cap,  guided  by  several  adjustments,  are  trimmed 
even  with  the  sides  of  the  root  and  the  post  soldered  in  position. 
B,  Fig.  246,  shows  the  cup-shaped  cap  with  post  ready  for  the  ad- 
justment of  the  porcelain  front,  which  is  attached  in  the  usual 
manner. 

Dr.  F.  T.  Van  Woert,  in  constructing  crowns  without  collars, 
shapes  the  end  of  the  root,  and  adapts  the  cap,  as  shown  in  Fig. 
247.  The  slant  given  to  the  palatal  side  aids  the  root  to  resist  force 
in  a  forward  direction. 

Partial  Collar  Crowns. — The  advantages  of  a  collar  can  in  a 


Fig.  245. 


Fig.  246. 


Fig.  247. 


Fig.  248. 


A 


great  measure  be  given  these  forms  of  post  or  dowel  crowns  by 
the  addition  of  a  metal  flange  encircling  the  palatal  section  of  the 
root,  as  shown  in  Fig.  248.  A  piece  of  gold  or  platinum,  similar 
in  shape  to  that  shown  at  A,  is  formed  and  fitted  to  the  crown, 
fixed  in  position  on  the  crown  with  wax,  and  adjusted  in  the 
mouth  against  the  surface  of  the  neck  of  the  root,  removed,  in- 
vested, and  soldered.  After  finishing,  the  metal  flange  is  bur- 
nished against  the  root  before  the  crown  is  cemented. 

Dr.  T.  F.  Chupein's  method  to  form  a  partial  collar-cap  for  a 
root  is :  Cut  a  strip  of  platinum  of  about  No.  32,  or  gold  plate  of 
No.  30  gage,  to  the  shape  shown  in  Fig.  249,  for  instance,  for  an 
incisor.  Bend  the  metal  to  the  form  illustrated  in  Fig.  250. 
Place  the  collar  on  the  root  with  the  broad  portion  at  the  labial 
side.     Grasp  the  ends  with  pliers  and  draw  the  metal  tightly  to- 


132  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 

gether  against  the  sides.  Remove  and  solder  the  ends  together 
(Fig.  251).  Trim  the  edge  of  the  collar  to  the  surface  of  the  root. 
Solder  on  a  thin  piece  of  platinum  plate  to  form  the  cap  (Fig.  252), 
and  remove  the  surplus  plate  and  projecting  ends  and  the  labial 
section  of  the  collar  (Fig.  253).  The  cap  is  then  ready  to  have  the 
post  fitted  and  soldered  to  it  in  position  (Fig.  254).  As  the  labial 
section  of  the  collar  assists  in  determining  the  exact  relation  of  the 
cap  to  the  root,  it  is  best  in  some  cases  not  to  remove  that  portion 
until  after  the  post  is  soldered. 

Fig.  249. 


Fig.  250.  Fig.  251.  Fig.  252.  Fig.  253.        Fig.  254. 


Post  and  Disk  Method. — Ready-made  posts  corresponding  in 
size  to  the  Ottolengui  reamers,  Fig.  96,  with  prepared  disks  of 
platinum,  can  be  used  to  facilitate  the  construction  of  crowns  of 
this  style. 

The  posts  are  illustrated  in  Fig.  257.     A  disk  of  platinum  with 


Fig.  255. 


a  perforated  depression  in  which  a  little  pure  gold  has  been  melted 
is  shown  in  Figs.  258  and  259. 

The  method  is  as  follows : 

Shape  the  surface  of  the  end  of  the  root  as  shown  in  Fig.  255. 

Trim  the  approximal  and  palatal  sides  of  the  end  of  the  root 
as  illustrated  in  Fig.  256,  but  leave  the  labial  side  A,  intact. 

Enlarge  and  ream  the  root-canal  with  Ottolengui  root-canal 
reamers,  shown  in  Fig.  96,  to  the  proper  depth,  first  using  the 
smallest  size,  and  if  necessary  the  larger  sizes  afterward. 

Select  a  post  (Fig.  257)  corresponding  in  number  to  that  of  the 


FORMS  OF  GOLD  CROWNS  1\YITH  PORCELAIN  FRONTS.       133 

reamer  used.  Seize  the  large  end  of  the  post  with  the  points  of 
the  pliers  and  fit  the  post  to  the  canal.  Move  the  post  up  and 
down — but  do  not  twist — a  few  times  in  the  canal,  and  any  slight 
discrepancy  that  may  exist  respecting  size  will  be  instantly  re- 
moved. 

Grasp  the  post  when  fitted  in  the  canal  with  the  pliers,  having 
the  points  close  to  the  surface  of  the  end  of  the  root.  Remove 
the  post  without  changing  the  relation  of  the  pliers.  Screw  the 
post  into  the  hole  in  the  depression  of  the  platinum  disk,  shown 
in  Fig.  258,  and  in  section  in  Fig.  259,  up  to  the  points  of  the 
pliers,-  thus  giving  the  post  its  position  in  the  disk. 

Bend  the  sides  of  the  disk  downward,  as  shown  in  Fig.  260, 
and  adjust  the  post  in  the  canal  to  determine  their  relative  posi- 
tions. By  twisting  the  post,  changes  of  its  position  in  the  disk 
may  be  effected,  also  by  pressing  the  post  further  through  the 
platinum  while  the  disk  is  in  position  on  the  root. 

Fig.  257.  Fig.  258.  Fig.  259.  Fig.  260. 


The  orifice  of  the  root-canal  should  be  slightly  enlarged  with 
a  round  bur  to  allow  the  depression  of  the  disk  to  fit  within  it. 
Press  the  post  firmly  upward  in  the  root-canal  to  assure  that  its 
original  position  is  not  interfered  with  by  the  disk. 

Remove  the  post  and  disk,  the  disk  retaining  its  position  on  the 
post.  Unite  post  and  disk  by  holding  them  in  a  Bunsen  gas  flame 
until  the  pure  gold  in  the  depression  is  fused.  oSTo  flux  is  neces- 
sary, as  sufficient  remains  from  the  fusion  of  the  gold  in  the  de- 
pression. 

Place  the  post  and  disk  on  the  root,  and  press  and  mallet 
the  platinum  to  it  with  a  large  flat  plugger,  which,  owing 
to  the  rigidity  of  the  post  in  the  canal,  will  accurately 
retain  the  platinum  in  position  on  the  end  of  the  rooL. 
Remove  and  slit  the  platinum  at  two  or  three  points 
between  the  palatal  and  approximal  sides  to  the  outline 
of  the  end  of  the  root,  as  shown  in  Fig.  261,  at  A  and  B, 
and  bend  the  platinum  over  with  the  pliers  to  embrace  the 
approximal  sides  of  the  root. 


134 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Again  place  the  post  and  cap  on  the  root,  and  closely  fit  the 
side  flaps,  with  the  aid  of  foot-shaped  condensers  and  burnishers. 
Next  bring  the  palatal  flap  down  to  position.  Frequent  removals 
and  annealings  are  necessary  during  the  process,  which  should 
include  the  final  trimming  of  the  edge  of  the  platinum,  smooth- 
ing with  a  corundum-point,  and  then  an  annealing  and  all-round 
burnishing  of  the  cap  to  the  root.  Cut  off  the  end  of  the  post 
above  the  cap  with  a  corundum-disk  and  level  with  a  wheel.  The 
Fig.  262.  Fig.  263. 


Fig.  265. 


Fig.  266. 


Fig.  267. 


cap  can  now  be  invested  and  the  seams  soldered,  or  this  can  be 
done  in  the  soldering  on  of  the  porcelain  front. 

At  the  cervico-labial  section  the  porcelain  can  rest  on  the  plati- 
num, or  the  platinum  can  be  trimmed,  so  that  the  front  edge  of 
the  porcelain  may  be  fitted  directly  against  the  root,  and  cover  it. 

The  remainder  of  the  construction  is  similar  to  that  of  a  full 
collar  crown,  described  at  page  88. 


FORMS  OF  GOLD  CROWNS  ^YITH  PORCELAIN  FRONTS.'      135 


The  Sanger  Method. — This  method,  presented  by  Dr.  K.  M. 
Sanger  to  simplify  the  construction  of  the  half-collar  cap  for 
crowns,  is  as  follows :  A  piece  of  pure  gold  plate,  gage  No.  30, 
is  cut  to  about  the  shape  of  Fig.  262.  Being  annealed,  it  is  grasped 
at  the  straightest  edge  (Fig.  262,  A)  with  a  pair  of  clasp-benders, 
and  hammered  down  to  the  flat  end  of  the  benders  with  a  small 
riveting  hammer  (Fig.  263)  until  it  assumes  the  shape  shown  in 
Figs.  264  and  265.  With  a  pair  of  curved  shears  it  is  cut  along 
the  collar  on  the  outside  at  A  A,  Fig.  264,  and  trimmed  down  so 
that  the  metal  tongue  will  pass  between  the  two  free  edges  of  the 
collar,  as  in  Fig.  266.  It  is  then  placed  on  the  root  in  the  mouth 
and  burnished  and  trimmed  to  fit,  carefully  removed  and  soldered 
along  the  free  edges  on  the  outside  and  the  points  cut  off,  result- 


Fig.  268. 


Fig.  269. 


Fig.  270. 


ing  in  a  half-collar  cap,  as  shown  in  Fig.  267.  The  remainder  of 
the  work  is  the  same  as  in  the  construction  of  any  backed  and 
soldered  crown. 

The  Double  Cap=Crown:  Dr.  Parr's  Method. — The  advantage 
of  this  form  of  crown  is  that  the  root  is  securely  and  permanently 
capped  independently  of  the  crown,  which  can  be  removed  without 
disturbing  the  cap  on  the  root.  For  use  in  crown-  and  bridge-work 
the  outer  cap  may  be  made  without  a  collar,  as  shown  in  Fig.  269, 
or  with  a  partial  collar,  which  half  encircles  the  inner  cap  over 
the  palatal  portion,  and  tapers  off  from  the  palatal  to  the  labial 
section,  as  illustrated  in  Fig.  270.  The  cap  on  the  root  is  cemented 
with  oxyphosphate,  and  the  post  and  outer  cap  with  gutta-percha. 

The  root  is  prepared,  banded,  and  capped  without  a  pin,  the 


136  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

same  as  for  a  gold  collar  crown  (A,  Fig.  268).  A  hole  is  made 
in  the  cap,  and  a  post  fitted  in  the  canal.  A  piece  of  pure  gold 
plate  or  platinum  is  cut  fully  the  size  of  the  surface  of  the  root 
cap.  The  plate  is  perforated  in  the  center  and  the  post  inserted 
into  the  hole,  which  it  should  fit  tightly.  The  post  is  next  inserted 
in  the  canal  and  the  plate  is  adapted  to  the  surface  of  the  root  cap 
and  around  the  post.  Post  and  cap  are  removed  and  soldered  to- 
gether, forming  an  outer  cap,  which  is  trimmed  evenly  with  the 
edge  of  the  root  cap  (B,  Fig.  268).  The  porcelain  tooth,  C,  to 
form  the  crown,  is  fitted  and  soldered  to  the  outer  cap.  When 
finished,  the  crown  is  cemented  in  position  with  gutta-percha,  as 
shown  in  Fig.  269. 

A  double  cap-crown  with  detachable  or  removable  crown  post, 
for  use  in  connection  with  detachable  or  removable  bridges,  is  de- 
scribed in  Part  III,  Chapter  XL 


CHAPTER    XII. 

Setting  All-Porcelain  Crowns  on  Capped  Roots. 

the  logan  :  dr.  white's  method— collar-cap— a  simple  method 
—the  davis  crown  on  a  capped  root. 

The  Logan  Crown.1— Prepare  the  end  of  the  root  and  the  canal 
in  the  usual  manner  and  adjust  in  proper  position  a  Logan  crown. 
Grind  the  palatal  side  of  the  base  of  the  crown  so  as  to  give 
it  the  slant  shown  in  A  and  B,  Fig.  271.  Take  a  disk  of 
platinum  foil  1/1000  to  1/500  in  thickness,  push  the  pin  of 
the  crown  through  it,  adjust  the  foil  closely  to  the  base  of  the 
crown,   and  secure  it  with  wax  cement,   as  seen  in   Fig.    272. 


Fig.  272.      Fig.  273.      Fig.  274.  Fig.  275. 


Trim  the  platinum  disk  to  the  edge  of  the  base  of  the  crown  so 
there  will  be  no  overlapping.  Next  place  a  small  ball  of  wax  on 
the  platinum  around  the  pin  and  over  this  wax  another  disk  of 
platinum  foil  (Fig.  273).  Heat  the  foil,  to  cause  adhesion  of  the 
wax,  by  rubbing  a  hot  instrument  over  its  surface,  and  chill  in 
water.  Insert  the  post  of  the  crown  in  the  root  and  press  the 
crown  to  position  and  occlude  the  teeth  to  positively  assure  its 
correctness.  The  pressure  of  the  wax  against  the  foil  shapes  it  to 
the  exact  form  of  the  surface  of  the  end  of  the  root.  Remove  and 
trim  the  second  platinum  disk  to  the  outline  of  the  root  (Fig.  274). 
If  the  palatal  side  of  the  root  is  trimmed  so  that  it  stands  a  little 

1  Dr.  Gordon  White's  method. 

137 


138  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

above  the  gum  line,  the  surplus  platinum  at  that  part  may  be  slit, 
lapped,  and  burnished  around  this  exposed  portion  to  form  a  partial 
band. 

The  wax  is  next  dried  with  bibulous  paper,  the  sides  properly 
shaped,  and  then  covered  with  two  triangular  pieces  of  platinum 
(Fig.  275).  Attach  the  platinum  to  the  wax  by  rubbing  a  hot  in- 
strument over  its  surface,  and  invest  the  crown.  When  the  invest- 
ment is  set,  wash  the  wax  out  with  boiling  water.  Heat  the  invest- 
ment and  flow  solder  in  between  the  two  pieces  of  platinum  and 
finish  in  the  usual  manner.  Porcelain  may  be  substituted  for  gold 
in  the  construction  by  this  method.  In  such  a  case,  the  disk  of 
platinum  next  to  the  crown  is  not  used,  the  wax  being  placed  on 
the  base  of  the  crown.  The  crown  should  be  invested  and  the  plati- 
num fastened  to  the  post  with  a  particle  of  pure  gold  to  retain  it  in 
position  while  the  triangular  space  is  filled  with  porcelain  body  and 
baked  (Part  IV,  Chapter  VI). 

CoIIar=Cap. — The  end  of  the  root  is  prepared,  a  gold  collar 

fitted,  and  the  collar  capped  with  platinum  foil  1/1000.     The  cap 

is  adapted  to  the  surface  of  the  end  of  the  root,  punctured,  and 

burnished  to  the  orifice  of  the  canal.     A  platinum  disk 

Fig^TG.      js  next  perforated  and  fitted  to  the  base  of  the  Logan 

crown,  the  same  as  in  the  method  previously  described, 

with  which  the  remainder  of  the  operation  is  identical 

(Fig.  276). 

A  Simple  Method.1 — Shape  the  end  of  the  root  for 
a  collar-cap,  and  bevel  it  off  at  the  cervico-labial  section 
if  exposure  of  the  collar  is  to  be  avoided.  Construct  a 
collar-cap  (Fig.  277).  Place  the  cap  on  the  root,  per- 
forate the  cap,  and  adapt  it  to  the  orifice  of  the  canal. 
Fit  a  Logan  crown  in  correct  position,  so  that  the  edge 
of  the  base  of  the  crown  accurately  fits  the  surface  of  the  cap. 
llemove  the  crown,  place  zinc  oxyphosphate  in  the  countersunk 
section,  and  adjust  in  the  mouth.  When  the  oxyphosphate  has  set, 
remove  the  crown  and  cap  and  solder  the  pin  on  the  inside  of  the 
cap  with  a  very  small  quantity  of  solder, — tin  and  lead, — using 
muriate  of  zinc  as  a  flux,  a  few  blasts  of  the  blowpipe  only  being 
required.  Place  the  cement  in  the  root-canal  and  cap  and  cement 
crown  in  position.     Fig.  278  shows  the  finished  crown. 

1  C.  S.  W.  Baldwin,  Dental  Cosmos,  January,  1S87. 


SETTING  ALL-PORGELAIN  CROWNS  ON  CAPPED  ROOTS.       139 

The  Davis  Crown  on  a  Capped  Root. — Grind  the  root  evenly 
to  the  gum-margin,  removing  al]  the  enamel  except  a  little  thatmay 


Fig.  277. 


Fig.  27s. 


Fig.  280. 


be  allowed  to  remain  at  the  palatal  <i»le,  and  give  the  labial  section 
of  the  root  a  slight  bevel.  This  bevel  is  for  the  purpose  of  permit- 
ting the  covering  of  the  band  at  this  point 
with  the  porcelain,  as  shown  in  Figs.  279  and 
280. 

Band  and  cap  the  root, giving  the  labial  side 
of  the  collar  a  slanting  form,andfit  and  solder 
in  the  Davis  pin,  as  shown  in  Fig.  279.  Take 
an  impression,  make  a  model  and  articulating 
model,  grind  the  crown  to  fit  the  cap  accurately 
all  around  the  edge  of  its  base,  and  to  fit  over 
and  cover  the  band  of  metal  at  the  labial  sec- 
tion. In  doing  this  use  small  corundum-points  and  a  paste  made  of 
a  mixture  of  rouge  and  oil,  with  which  paint  the  surface  of  the  cap 
for  the  purpose  of  marking  on  the  porcelain  the  points  of  contact. 
When  the  crown  is  accurately  ground  to  fit  the  cap  by  the  model, 
it  is  advisable  to  positively  assure  the  correctness  of  its  alignment. 
The  crown  is  next  cemented  on  the  cap  and  the  cement  allowed  to 
set  with  the  crown  removed  from  the  mouth.  Fig.  280  shows  the 
finished  crown  attached  to  the  root,  which  may  be  done  with  gutta- 
percha or  oxyphosphate.  Bicuspids  can  be  made  in  a  similar 
manner. 

The  use  of  porcelain  in  its  application  to  this  crown  by  the  above 
method  is  explained  in  Part  IV,  Chapter  VI. 

11 


CHAPTER    XIII. 

Treatment  by  Crown-Work  of  Fractured  Teeth  and  Roots 
and  Cases  of  Irregularity. 

fractured  crowns  and  roots— longitudinal  fracture— slant- 
ing fracture  of  the  root— restoration  by  banding  and 
capping— inlay  method— amalgam— post  and  amalgam— per- 
foration of  a  side-wall  of  a  root-canal  or  of  the  dentin 
at  the  bifurcation  of  the  roots — dr.  farrar's  cantilever 
crown — formation  of  the  spur— methods  of  crowning  in 
cases  of  irregularity. 

The  crowning  of  fractured  teeth  and  roots  is  a  process  that  re- 
quires skill  and  delicate  treatment.  Its  practicability  depends  on 
the  nature  of  the  fracture,  the  present  health  of  the  parts,  and  the 
length  of  time  that  has  elapsed  since  the  occurrence  of  the  injury. 

Longitudinal  Fracture.- — By  this  is  meant  a  fracture  extending 

lengthwise  through  the  crown  or  what  remains  of  it,  and  along  the 

root  or  roots.     Foreign  substances  having  been  removed  from 

within  and  around  the  parts,  the  crevice  of  the  fracture  is  syringed 

thoroughly  with  tepid  water  and  then  with  hydrogen  peroxid. 

The  fractured  parts  of  the  root  are  then  drawn  together  with 

waxed  floss  silk,  passed  at  least  twice  around  the  tooth, 
Fig    28]  . 

and    tied,    the    ends    being    passed    through    twice    in 

®  forming  the  knot.  The  pulp-chamber  is  then  pre- 
pared, and  dovetail  slots  are  drilled  across  the  parts 
(Fig.  281). 
If  it  is  suspected  that  in  the  preparation  any  particles  of 
dentin  have  invaded  the  crevice  of  the  fracture,  the  ligature 
must  be  removed,  the  parts  again  syringed,  and  the  ligature  read- 
justed. The  upper  parts  of  the  root-canals  are  then  filled  with 
gutta-percha,  or,  preferably,  with  zinc  chlorid,  and  the  main 
body  of  the  cavity  and  the  slots  with  a  hard,  quick-setting  amal- 
gam.    Another  method  is  to  drill  the  line  of  one  of  the  root-canals 

140 


TREATMENT  BY  CROWN-WORK  OF  FRACTURED  TEETH.       14j[ 

as  deeply  as  possible  parallel  to  that  of  the  other,  fit  a  post  in  each, 
and  connect  the  two  together  with  a  piece  of  plate,  as  shown  in 
Fig.  2S2,  and  cement  the  posts  in  the  roots. 

At  the  next  visit  of  the  patient  the  ligature  is  re-  FlG-  282- 
moved  and  the  parts  carefully  prepared  for  crowning. 
The  circumference  of  the  root  is  first  measured  with  a 
wire,  a  tight-fitting  collar  constructed,  and  the  crown 
then  completed  in  the  usual  manner.  The  crown  may 
be  favored  by  leaving  a  slight  space  between  its  occlud- 
ing surface  and  the  antagonizing  tooth. 

The  great  drawback  in  these  cases  is  that  the  patient  generally 
fails  to  present  himself  immediately  for  treatment,  and  foreign 
substances  work  into  the  fracture,  causing  inflammation,  which  is 
difficult  to  control.  Often  subsequent  to  treatment  a  septic  con- 
dition of  the  fracture  supervenes,  the  irritation  caused  thereby 
and  the  exudations  from  the  fracture  becoming  so  annoying  that 
extraction  is  the  only  alternative. 

Teeth  fractured  as  above  described  are  rarely  found  with  living 
pulps. 

Slanting  Fracture  of  the  Root. — Fractures  of  this  kind  are 
frequently  found  in  incisors  or  cuspids  and  in  bicuspids. 

In  the  incisors  or  cuspids  the  fracture  is  generally  caused  by  the 
leverage  or  strain  that  has  been  exerted  by  the  post  of  a  collarless 
crown.  The  crown,  if  still  in  position,  will  be  found  loose,  the 
fractured  piece  of  root  adhering  loosely  to  the  membranes  and 
the  remaining  portion  of  the  root  firm. 

The  crown  and  loosened  portion  of  the  root  are  removed  and 
the  latter  preserved  for  use  as  a  pattern.  The  hemorrhage  is 
checked  with  styptics  and  the  parts  anesthetized  with  cocain.  The 
space  between  the  root  and  gum  is  packed  with  gutta-percha  to 
force  back  the  gum  and  to  expose  and  give  free  access  to  the  mar- 
gins of  the  fracture,  after  which  the  patient  is  dismissed.  In  two 
or  three  days  the  gum  will  have  healed,  so  that  on  the  removal  of 
the  dressing  little  or  no  hemorrhage  will  occur  to  interfere  with 
the  work. 

Restoration  of  the  Fractured  Part  by  Banding  and  Capping. 
— In  a  case  of  this  kind  (Fig.  283)  the  restoration  of  the  fractured 
part  by  banding  and  capping  for  crowning  purposes  is  as  follows : 
A  piece  of  soft  platinum  plate,  gage  ]STo.  32,  is  cut  to  about  the 
shape  of  Fig.  284,  the  fractured  piece  being  used  to  determine  the 


142 


GROWN-,  BRIDGE-,  AXD  PORCELAIN  MORE. 


shape  and  size  of  the  apron  portion  (Fig.  284,  A),  while  the  wings 
(B  B,  Fig.  284)  are  made  sufficiently  long  to  reach  around  the 
entire  root  in  the  form  of  a  collar.  With  an  ordinary  pair  of 
clasp-benders  the  platinum  is  shaped  to  fit  the  fractured  piece  of 
root  (Fig.  285),  and  it  is  then  placed  in  the  mouth  and  the  wings 
are  brought  around  the  root  to  complete  the  collar  form.  It  is 
then  removed  and  soldered,  and  forms  a  collar  with  an  apron  as 
represented  in  Fig.  286.  A  piece  of  flat  platinum  plate,  gage 
No.  30,  is  then  placed  across  the  end  of  the  collar  mesio-distally 
and  soldered  to  the  edge  (Fig.  287,  A  A).  It  is  then  placed  back 
on  the  root  and  perforated  for  the  reception  of  the  tube  and  pin. 
A  seamless  platinum  tube  is  procured  by  fracturing  an  Ash  tube- 


Fig.  283. 


Fig.  2S4.  Fig.  285. 


Fig.  286.  Fig.  287. 


Fig.  2SS.  Fig.  2S9. 

IH<-B  A^ 


m^A 


tooth.  A  piece  of  round  platino-iridium  wire  which  perfectly  fits 
the  tube  is  passed  through  the  tooth  and  held  in  position  while 
the  tooth  is  broken  away  from  the  tube,  thus  preventing  the 
marring  of  the  tube,  providing  a  strong  platinum  tube  with  a  pin 
which  fits  it  exactly.  A  suitable  tube  may  be  formed  out  of  plati- 
num foil  or  very  thin  plate. 

With  the  collar  apron  in  position  on  the  root,  the  tube  and  pin 
are  pushed  through  the  perforation  and  up  into  the  canal  as  far  as 
possible,  and  then  with  a  sharp  instrument  the  tube  is  split  and 
folded  down  on  the  flat  piece,  as  illustrated  at  B,  Fig.  2S7.  It  is 
then  removed  and  soldered,  giving  the  construction  represented 
by  Fig.  288,  which  is  ready  for  final  placing  on  the  root. 

The  method  of  setting  is  as  follows:     The  pin  is  placed  in 


TREATMENT  HY  CROWN-WORK  OF  FRACTURED  TEETH.       143 

the  tube  to  prevent  the  oxyphosphate  from  passing  into  the  tube 
and  to  serve  as  a  handle  to  hold  the  piece  firmly  while  pack- 
ing the  amalgam.  A  small  amount  of  cement  is  placed  in  the 
canal  and  around  the  point  of  the  tube  (Fig.  288,  A),  also  around 
the  inside  of  the  band,  where  it  engages  the  root  (Fig.  288,  B). 
The  piece  is  then  placed  on  the  root  and  held  firmly  until  the 
cement  hardens,  when  the  remainder  of  the  space  around  the  pin, 
and  between  the  apron  and  the  root  where  the  fracture  occurred, 
is  packed  with  a  quick-setting  amalgam  through  the  openings 
at  A  A,  Fig.  289.  The  last  illustration  (Fig.  289)  shows  the  work 
completed  and  ready  for  the  reception  of  the  crown.1 

Inlay  Method. — The  inlay  method  of  restoration  of  an  exten- 
sive fracture  of  a  root  for  the  purpose  of  capping  with  a  porcelain 
and  platinum  jacket-crown  or  an  all-gold  cap-crown,  is  as  follows : 
Fit  a  substantial  post,  the  point  of  which  will  extend  deepdy  in  the 
canal  (Fig.  290).  Cut  a  piece  of  platinum  foil  of  about  1/500  of 
an  inch  gage  and  of  a  size  which  will  a  little  more  than 
cover  the  end  of  the  root  and  the  fractured  section. 
Place  the  platinum  foil  over  the  parts,  and  press  it  in 
the  orifice  of  the  canal.  Puncture  and  adapt  it  to  the 
part  and  insert  the  post  in  position.  Cement  post  to 
platinum  with  wax.  withdraw,  invest,  and  solder  to- 
gether with  an  atom  of  pure  gold.  Next  adjust  the 
post  and  platinum  to  the  root,  and  by  repeated  fitting 
and  trimming,  using  a  very  small  burnisher,  adapt  the 
platinum  to  the  edges  of  the  fractured  portion  and  the  surface  of 
the  end  of  the  root.  The  platinum  should  only  cover  the  sur- 
face of  the  fracture  to  the  margins  and  not  extend  beyond  them. 
Accuracy  in  this  respect  is  accomplished  by  first  burnishing  the 
platinum  to  and  just  over  the  edge  of  the  fracture  so  that  the 
shape  and  form  of  the  part  is  impressed  on  the  metal,  which,  when 
removed,  can  be  trimmed,  guided  by  this  mark,  to  accurately 
meet  the  fracture,  but  not  extend  over. 

Wax  is  next  shaped  upon  the  platinum  to  represent  the  lost 
portion  of  the  root.  The  surface  of  the  wax  representing  the  side 
of  the  lost  part  is  covered  with  platinum  foil  from  1/2000  to 
1/1000  of  an  inch  in  thickness,  trimmed  to  just  meet  the  margin 
of  the  platinum  at  the  line  of  the  fracture.     The  free  or  open  end 

'Dr.  R.  M.  Sanger's  method. 


144  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

of  the  platinum  should  extend  outside  of  the  gum-margin,  as 
shown  at  P,  Fig.  290.  The  work  is  next  invested  upright  with 
the  open  end  exposed,  the  wax  washed  out  with  boiling  water,  and 
gold  plate  or  solder  is  melted  in  its  place,  as  indicated  at  S,  Fig. 
290,  and  around  the  post.  When  soldered,  the  margins  of  the 
inlay  are  smoothed  and  it  is  cemented  with  oxyphosphate.  After 
the  cement  has  set  the  surplus  at  the  margins  should  be  carefully 
removed.  This  method  when  well  done  gives  an  almost  imper- 
ceptible line  of  union  between  the  metal  and  the  root.  The  root 
is  then  ready  to  be  mounted  with  a  platinum  and  porcelain  jacket- 
crown  (see  Part  IV,  Chapter  VI)  or  a  metallic  crown. 

Amalgam. — Both  of  these  methods  present  a  non-oxidizable 
surface  of  metal  against  which  the  tissues  will  heal  benignly, 
which  is  not  the  case  when  amalgam  is  used  and  its  surface  is  left 
exposed,  even  though  polished.    The  use  of  amalgam  is  therefore 

Fig.  291.  Fig.  292.  Fig.  293. 


best  confined  to  comparatively  small  fractures  and  to  decay  ex- 
tending under  the  gum. 

Fractures  of  the  crown  and  side  of  the  root  occur  in  bicuspids, 
where  large  fillings  are  inserted  extending  from  the  anterior  to 
the  posterior  approximal  walls,  leaving  the  separated  buccal  and 
palatal  cusps  to  bear  the  brunt  of  mastication.  The  fracture 
seldom  extends  beyond  the  edge  of  the  alveolar  process.  The 
fractured  part  having  been  carefully  removed,  a  dovetail  slot  is 
made  in  the  crown  or  root,  in  which  gutta-percha  is  inserted  for  a 
day  and  the  gum  pressed  back,  so  as  to  fully  expose  the  surface 
and  margins  of  the  fracture.  The  form  of  the  neck  is  then  in  a 
measure  restored  with  amalgam,  which,  when  hard,  is  polished 
(Figs.  291  and  292).  The  tooth  or  root  is  then  crowned,  the  mode 
of  operation  being  the  same  as  in  any  other  case. 

Post  and  Amalgam — A  post  in  the  root-canal  gives  greater 
security  in  connection  with  amalgam  in  cases  that  suggest  it,  as 


TREATMENT  BY  CROWN-WORK  OF  FRACTURED  TEETH.       ^45 

illustrated  in  Fig.  293.  The  post  should  be  made  of  platinum 
with  a  globule  of  gold  solder  melted  on  the  part  which  rests  in 
contact  with  the  amalgam.  The  use  of  posts  made  of  alloys  of  the 
base  metals  is  not  permissible  in  these  operations.  When  amal- 
gam is  used  to  restore  a  fractured  root,  the  collar  of  the  crown  to 
be  inserted  is  supposed  to  nearly  or  entirely  cover  it. 

Perforation  of  a  Side=WalI  of  a  Root=Canal  or  of  the  Dentin 
at  the  Bifurcation  of  the  Roots. — Extensive  perforation  by  de- 
cay of  the  root  of  a  tooth  below  the  line  of  the  edge  of  the  alveolar 
process  seldom  admits  of  successful  treatment.  When  the  decay 
is  of  limited  extent,  and  a  very  slight  perforation  has  been  pro- 
duced by  its  thorough  removal  or  by  the  improper  or  careless  use 
of  a  bur,  cicatricial  tissue  may  be  induced  to  form  over  the  part 
by  creating  and  maintaining  a  sterilized  condition,  and  then  seal- 
ing the  cavity. 

The  method  of  procedure  is  as  follows :  First  effect  steriliza- 
tion of  the  dentin  and  canals.  Bathe  the  perforated  part  with 
hydrogen  dioxid.  Dry  the  canal  thoroughly.  Fit  closely  over 
the  perforation  a  small,  flat  piece  of  gutta-percha,  warmed  and 
applied  with  a  gentle  pressure,  sufficient  only  to  produce  adhesion 
without  forcing  the  gutta-percha  through.  The  filling  of  the 
canal  can  then  be  carefully  completed.  Zinc  oxychlorid  is  the 
most  suitable  in  these  cases,  as  no  pressure  is  required,  and  a  dense 
antiseptic  filling  in  the  roots  and  over  the  cap  on  the  perforation  is 
the  result.  If  this  method  proves  unsuccessful  and  inflammation 
ensues,  the  position  of  the  perforation  should 

"Fit    ^O'-t 

'  be  carefully  calculated,  and  an  artificial 
fistula  should  be  formed  on  a  direct  line  with 
it  through  the  gum  and  alveolar  process.  (See 
Fig.  294.)  Carbolic  acid  may  be  used  to  ob- 
tund  the  tissue  as  described  at  page  30.  The 
necessary  perforation  through  the  alveolar 
process  should  be  small  in  diameter,  and  be 
made  with  a  drill.  Frequently  the  position  for  the  intended  fistula 
is  best  located  by  introducing  a  sharp-pointed  probe  through  the 
canal  and  perforation  externally  through  the  tissues.  Injections 
then  can  be  made  outward  through  the  fistula,  and  the  perforation 
sealed  with  gutta-percha  similarly  to  the  closing  of  a  foramen  in 
cases  of  alveolar  abscess,  after  having  previously  filled  the  canal 
or  canals  above  the  perforation. 


140 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 


Crowning  Molar  Roots  Decayed  Apart  at  the  Bifurcation. — 

The  roots  of  a  molar  decayed  apart  at  the  bifurcation  can  often 
be  crowned  serviceably  by  making  a  cap  for  each  root  separately, 
and  then  soldering  the  sides  of  the  caps  together  (Fig.  295). 
Where  one  root  is  missing,  the  other  can  be  crowned  singly. 

Dr.  Farrar's  Cantilever  Crown. — Figs.  296  and  297  represent 
cantilever  crowns.     Fie\  296  illustrates  a  sectional  view  of  three 


teeth,  and  an  amputated  first  bicuspid  root  which  was  subsequently 
extracted,  showing  the  application  of  the  cantilever  crown  T  P, 
set  upon  the  decayed  second  bicuspid  and  made  to  project  over  to 
bridge  the  space  formed  by  the  loss  of  the  first  bicuspid,  and  rest- 
ing in  contact  with  the  cuspid  so  as  to  connect  the  broken  line  of 


Fig.  296. 


s^\ 


•■  t^Ov  , 


masticating  surfaces 

bicuspid.1  Fig.  297 
posterior  half  of  one 
plication  of  two  cap 
a  cantilever  bridge 
a  manner  as  to  piw 
same  time  be  easilv 


and  prevent  tilting  forward  of  the  second 
illustrates  the  appearance  of  two  molars,  the 
of  which  was  destroyed,  showing  also  the  ap- 
•crowns,  which  are  constructed  so  as  to  form 
over  the  chasm  by  locking  midway  in  such 
ent  tilting  or  sliding  of  surfaces,  and  at  the 
cleansed  by  a  quill  or  thread. 


Dr.  J.  X.  Farrar,  Dental  Cosmos,  vol.  xxvi.  Xo.  3. 


TREATMENT  BY  CROWN-WORK  OE  FRACTURED  TEETH.       147 


Formation  of  a  Spur. — A  spur  to  bridge  a  space  in  cases  such 
as  have  been  described  is  conveniently  formed  by  first  attaching 
the  edge  of  a  piece  of  heavy  platinum  foil  to  the  side  of  the  gold 
crown  with  wax  or  solder,  as  shown  in  Fig.  298.  The  crown  is 
then  fitted  in  the  mouth  and  the  platinum 
bent  and  burnished  over  against  the  adjoin- 
ing tooth  or  crown,  removed,  invested,  and 
solder  flowed  in  the  aperture  at  A.  The 
surplus  metal  is  to  be  trimmed  away  on  re- 
adjustment in  the  mouth. 

Methods  of  Crowning  in   Cases  of   Irregularity. — Fig 
represents  a  case  of  irregularity  treated   by   Dr.    Bonwill. 

Fig.  299. 


299 
On 


V 


v    v 


Fig.  300. 


account  of  the  poor  character  of  the  teeth,  their  position  in  the 
palatal  arch,  and  the  age  of  the  patient,  it  was  beyond  correction. 
The  pulps  were  destroyed,  the  crowns  removed,  posts  fitted  to  the 
canals,  and  the  ends  of  the  roots 
capped.  An  impression  was  taken 
which  removed  the  caps,  and  a 
model  and  articulating  model  made, 
which  showed  the  caps  in  posi- 
tion. Porcelain  fronts  were  backed 
and  fitted  in  correct  alignment  with 
the  other  teeth  and  connected  to 
the  caps  with  a  strip  of  platinum 
reinforced  with  solder.  The  model 
under  the  strips  was  scraped  suf- 
ficiently to  cause  them  to  press 
against  the  gum. 

Fig.    300  shows  a  method  of  treating  a  case  of  irregularity 
without   destroying  the  vitality  of  the  pulp.      The  tooth   at  B, 


148  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

which  stood  inside  the  line  of  the  lower  teeth  when  the  mouth 
was  closed,  was  trimmed,  shaped,  and  capped  without  destroying 
the  pulp.  To  this  cap  was  attached  the  tooth  A,  with  an  oval- 
shaped  piece  of  gold  for  cleanliness  that  cleared  the  lower  teeth  in 
occlusion.  The  cap,  which  was  then  cemented  to  the  natural 
crown,  was  entirely  hidden  from,  view  by  the  artificial  tooth  or 
porcelain  front. 


CHAPTER    XIV. 

Partial  Crown-Work, 

gold-plate  partial  crowns— gold  hollow  or  box  inlays— solid 
gold  inlays  with  extensive  restoration  of  contour — solid 
gold  tips  for  abraded  pulpless  front  teeth— gold  tips 
in  cases  of  living  pulps— extensive  restoration— porce- 
lain and  gold. 

Gold=Plate  Partial  Crowns. — This  is  one  of  the  forms  of 
partial  crown-work  which  may  be  adopted  with  advantage  when, 
for  any  reason,  the  insertion  of  a  solid  metallic  filling  or  inlay 
is  not  desirable.  The  cavity  having  been  properly  excavated, 
its  orifice  is  trimmed  as  uniformly  straight  or  circular  as  its 
position  and  character  will  allow,  and  the  edge  of  the  enamel 
beveled  off,  tapering  toward  the  center.  Deep  or  extensive  under- 
cuts may  be  filled  with  oxyphosphate.  In  the  preparation  of  cavi- 
ties in  the  grinding-surface,  trimming  and  cutting  away  the 
enamel  should  be  confined  to  that  surface.  In  approximal  cavities 
which  reach  the  grinding-surface,  it  is  advisable  to  extend  them 
into  that  surface  and  bring  the  gold  over  and  anchor  it  there,  so 
as  to  afford  greater  security  against  its  displacement  in 
mastication.  The  bicuspid  shown  in  Fig.  301  will  Fig.  301. 
serve  as  a  typical  case  to  illustrate  the  constructive 
details. 

The  cavity  having  been  properly  prepared,  a  die  of 
the  tooth  in  its  original  form  is  then  secured.  For 
this  purpose  the  mold  is  made  by  taking  an  impression  of  the  tooth 
with  wax  or  impression-compound,  making  a  plaster  model,  and 
then  restoring  the  contour  and  forming  from  it  the  mold  in 
moldine;  or  the  shape  of  the  natural  tooth  may  be  restored  with 
wax  or  gutta-percha  and  the  mold  made  directly  from  it  with 
plaster  in  a  tube.  The  die  and  counter-die  having  been  formed 
(see  Part  V,  Chapter  III),  a  piece  of  pure  gold,  Xo.  28  to 
30  standard  gage,  the  exact  thickness  being  goArerned  by  the 
size  and  nature  of  the  cavity,  is  struck  up  to  the  form  and  size 

149 


150 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  302. 


KiG.  303. 


of  the  part  to  be  capped.  The  gold  is  then  adjusted  to  the  cavity, 
to  the  margin  of  which  the  edges  are  trimmed  and  burnished  to  fit 
close  and  flush.  In  the  case  of  large  cavities,  including  a  part  or 
the  whole  of  the  approximal  surface,  a  plaster  model  of  the  tooth 
and  of  the  empty  cavity  from  an  impression  taken  in  wax  or  im- 
pression-compound will  facilitate  and  guide  the  preliminary  trim- 
ming and  shaping  of  the  gold.  Two  headed  pins  fixed  on  the 
inside  of  the  cap  (Fig.  302)  are  usually  sufficient 
to  secure  it,  but  others  can  be  added  if  the  condi- 
tions of  the  case  seem  to  require  it.  In  compound 
cavities,  including  one  side  and  the  grinding-sur- 
f ace,  one  pin  at  least  should  be  fixed  in  the  latter 
portion.  Where  the  grinding  and  both  approximal 
surfaces  are  included,  a  wire  should  be  extended 
from  one  side  to  the  other  (Fig.  303),  but  the  brace 
should  not  touch  the  bottom  of  the  cavity. 

In  pulpless  teeth  the  pin  from  the  upper  part  of 
the  cap  should  extend  up  the  canal,  which  gives 
great  stability  in  such  cases  (Fig.  304). 

In  soldering  the  pins  or  loops  to  the  gold  plate,  a 
little  solder  can  be  flowed  over  the  adjacent  parts  if 
deemed  necessary  to  stiffen  and  strengthen  them. 

Oxyphosphate,  as  a  rule,  is  preferably  used  for 
the  cementation  of  these  caps,  as  it  forms  a  solid 
and  unyielding  foundation,  and,  when  properly 
protected  from  the  fluids  of  the  mouth  by  a  care- 
fully adjusted  cap,  is  very  durable. 

The  cement  should  be  first  inserted  in  the  cavity, 
and  then  a  small  quantity  placed  around  the  pins 
of  the  cap,  which  should  be  immediately  adjusted  accurately  in 
position.  When  gutta-percha  is  used,  it  is  heated  and  applied 
in  the  same  manner  to  cavity  and  cap.  The  cap  is  then  heated, 
pressed  into  position,  and  held  there  until  the  gutta-percha 
hardens.  This  can  be  hastened  by  the  application  of  cold  water 
from  a  syringe.  The  surplus  of  gutta-percha  is  then  removed, 
and  the  edges  of  the  gold  burnished. 

These  caps  applied  to  teeth  with  living  pulps  show  durability 
of  a  commendable  character.  The  advantage  they  possess  over 
pieces  of  porcelain  is  found  in  the  close  joint  that  can  be  made 
with  the  edce  of  the  enamel  by  burnishing  the  gold  against  it. 


Fig.  304. 


PARTIAL  CROWN-WORK.  151 

Gold  Hollow  or  Box  Inlays.1 — These  consist  of  a  hollow  inlay 
made  by  first  forming  a  gold  matrix  of  the  cavity  and  then 
capping  the  matrix  with  another  piece  of  plate  contoured  to 
represent  the  lost  section  of  the  tooth.  The  process  is  as  follows: 
The  margins  of  the  cavity  should  be  made  either  square  or  slightly 
beveled  and  smooth.  When  the  edge  of  the  enamel  wall  is  weak 
it  should  be  beveled  to  protect  it  by  the  overlapping  edge  of  the 
gold  inlay.  All  undercuts  should  be  removed,  or  filled  in  with 
cement  as  the  conditions  suggest.  The  object  is  to  give  as  much  as 
possible  a  spoon-shaped  form  to  the  cavity.  An  impression  is  taken 
with  impression-compound.  A  small  pointed  piece  of  the  com- 
pound is  first  warmed  over  an  alcohol  flame  and  passed  into  the 
cavity  of  the  tooth,  and  the  rest  of  the  compound  instantly  pressed 
to  position  and  cooled  with  water  before  removal.  The  impres- 
sion and  "bite"  can  be  taken  together;  or,  if  not,  the  bite  can  be 
afterward  taken  in  wax.  The  patient  is  then  dismissed  until  the 
next  appointment.  The  part  representing  the  tooth  and  cavity  in 
the  impression  is  filled  with  either  copper  amalgam  or  oxyphos- 
phate,  and  the  remainder  of  the  impression  with  plaster.  In 
packing  the  amalgam  or  oxyphosphate  a  small  portion  should  lie 
built  up  to  engage  the  cement  and  to  hold  it  firmly  in  position  in 
the  plaster.     An  articulating  model  is  next  made. 

Pure  gold,  about  No.  30  gage,  is  used  to  make  the  inlay  shell. 
A  piece  of  this  thin  gold  plate,  of  a  size  considerably  larger  than 
the  cavity,  is  pressed  and  burnished  to  the  shape  of  the  cavity  on 
the  model  with  burnishers  and  pellets  of  cotton.  The  gold  should 
be  trimmed  so  as  to  everywhere  barely  overlap  the  margins  of  the 
cavity  and  burnished  so  as  to  distinctly  mark  the  line  of  the  mar- 
gins on  the  gold.  In  the  central  or  axial  section  of  the  gold 
matrix  a  hole  of  the  proportion  illustrated,  in  the  ma- 
trix, Fig.  305,  is  then  punched.  The  cap  or  outer  shell 
of  the  matrix  for  an  approximal  or  buccal  cavity, 
where  the  restoration  required  is  not  extensive,  is  made 
as  follows :  A  piece  of  pure  gold  of  the  same  thickness 
as  the  matrix  is  cut  large  enough  to  extend  over  the  entire  surface 
to  be  restored.  One  edge  is  trimmed  and  fitted  to  come  just 
within  the  cervical  margin  of  the  gold  matrix  and  is  then  united 
with  a  tiny  piece  of  22-carat  gold  plate. 

1  Dr.  H.  B.  Tileston. 


152  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

The  matrix  is  put  back  on  the  model,  where  the  piece  of  plate 
soldered  to  it  will  stand  straight  up  above  the  occluding  surface  of 
the  tooth.  Wet  cotton  is  then  packed  into  the  cavity  between  the 
two  pieces  and  the  gold  forced  out  so  as  to  give  the  desired  form 

to  the  part  or  knuckle  it  against  the 
adjoining  tooth  (Fig.  306).  The 
gold  is  next  bent  over  the  cotton  and 
down  upon  the  occluding  surface, 
and  the  articulating  model  closed 
tightly  together  and  the  thin  gold 
forced  into  proper  articulating  form. 
Holding  the  models  firmly  closed, 
the  gold  is  bent  clown  all  around  to  the  edges  of  the  matrix,  using 
foot-shaped  condensers  and  burnishers,  the  cotton  being  tucked  in 
when  in  the  way. 

The  edge  of  the  cap  or  outer  piece  of  gold  is  next  trimmed 
so  as  to  come  within  the  excess  of  gold  provided  in  the  matrix 
piece,  and  so  the  margin  will  lie  as  nearly  as  possible  along  the 
true  line  of  the  margin  of  the  cavity.  This  arrangement  allows 
the  soldering  to  be  easily  and  properly  performed  and  provides 
an  overlap  of  thin  gold  for  the  final  burnishing  and  finishing. 
The  cotton  is  next  removed  either  by  raising  the  cap  or  pulling 
it  out  through  the  hole  in  the  back  of  the  matrix. 

At  the  next  visit  of  the  patient  the  inlay  is  adjusted  in  the 
tooth,  corrected,  and  perfected  both  as  to  accuracy  of  fit  and 
occlusion.  The  edges  are  soldered  together  with  very  small  pieces 
of  22-carat  plate,  which  are  placed  along  the  seam  on  the  little 
ledge  formed  there  by  the  surplus  of  the  gold  which  forms  the 
matrix. 

The  interior  is  next  partly  filled  with  18-carat  solder  by  drop- 
ping small  pieces  through  the  hole  in  the  back  and  fusing  by 
holding  the  inlay  in  a  spirit  or  Bunsen  flame. 

The  surplus  gold  at  the  edges  of  the  matrix  should  be  trimmed 
and  polished,  the  inlay  again  inserted  in  the  cavity,  and 
the  edges  again  burnished  (Fig.  307). 

The  inlay  is  then  removed,  the  cavity  in  the  back  filled 
with  cement,  and  the  inlay  cemented  in  position.  While 
the  cement  is  soft,  the  edges  of  the  inlay  should  be  bur- 
nished all  around  the  cavity  so  as  to  bring  the  gold  against  the 
enamel  at  every  point  and  leave  no  cement  exposed. 


PARTIAL  CROWN-WORK.  I53 

When  the  cement  has  set,  the  edges  may  be  additionally  trimmed 
and  burnished. 

In  a  case  demanding  extensive  restoration  of  contour,  where 
the  method  above  described  is  not  applicable,  the  desired  contour 
may  be  built  out  and  carved  with  wax  or  plaster,  from  which  a 
die  and  counter-die  are  made  and  the  outer  piece  of  plate  struck 
up.  Or  a  quicker  way,  and  one  giving  about  as  good  results,  is 
to  carve  up  the  contour  in  plaster  placed  in  the  matrix,  press  this 
model  into  warmed  sealing-wax  or  Dental  Lac,  and  burnish  a  piece 
of  gold  plate  into  the  intaglio  die  thus  obtained.  Adjust  and 
correct  the  plate  on  the  model  with  burnishers  and  pliers. 

Solid  Gold  Inlays. 

This  form  of  gold  inlay  is  used  in  the  front  teeth  as  well  as 
the  back  ones.  It  is  especially  suitable  in  operations  where 
strength  and  resistance  to  the  force  of  occlusion  and  attrition  are 
required  to  a  degree  not  afforded  by  a  filling  of  pure  gold. 

For  Small  or  Medium=Sized  Cavities  in  the  Front  or  Back 
Teeth,  the  sides  of  the  cavity  are  shaped  straight  or  slanting 
slightly  toward  the  center.  The  matrix  is  made  of  pure  gold 
No.  38  gage  or  platinized  gold  composed  of  pure  gold  alloyed 
with  2  per  cent,  of  platinum,  1/500  of  an  inch  in  thickness. 
Platinized  gold  of  such  a  gage  is  much  to  be  preferred  to  the 
heavier  gage  of  pure  gold.  It  is  more  conveniently  manipulated, 
especially  in  small  cavities  and  narrow  spaces,  and  because  of  the 
presence  of  the  platinum  is  not  so  liable  to  be  accidentally  melted 
in  the  construction  of  the  inlay. 

The  piece  of  the  motal  selected  to  form  the  matrix  should  be 
cut  large  enough  to  line  the  cavity  and  extend  about  £  of  an 
inch  beyond  the  margins.  It  is  placed  over  the  orifice,  pressed 
into  the  cavity,  and,  with  small  round-headed  burnishers,  bur- 
nished to  the  walls.  The  surplus  around  the  orifice  is  next 
brought  down  and  burnished  to  the  edge  of  the  cavity  and  the 
surrounding  surface  of  the  enamel. 

The  matrix  is  removed,  and  a  very  small  quantity  of  solder  is 
placed  and  fused  in  the  bottom  by  holding  in  a  spirit  or  gas  flame. 
Only  enough  solder  should  be  applied  to  barely  cover  the  bottom, 
so  as  to  leave  the  sides  intact.  Fluxed  solder  filings  are  the  most 
suitable  for  the  purpose.   The  matrix  is  next  adjusted  in  the  cavity, 


154 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


very  accurately  adapted  to  the  margins,  and  a  piece  of  Moss  Fibre 
gold  is  packed  in  the  bottom  of  the  matrix,  and  attached  by  again 
holding  the  matrix  in  the  flame  and  heating  sufficiently  to  slightly 
fuse  the  solder  already  applied.  To  the  Moss  Fibre  gold  so  at- 
tached enough  more  is  added  to  fill  the  matrix  and  shape  it  to  any 
required  form.  Solder  is  next  placed,  a  little  at  a  time,  on  the 
surface  of  the  Moss  Fibre  gold,  and  fused.  Only  enough  solder 
to  fill  the  porous  structure  of  the  Moss  Fibre  gold  and  form  a  solid 
inlay  should  be  used,  as  an  excess  necessitates  the  labor  of  its  re- 
moval. After  soldering  and  adjusting  in  the  mouth,  should  the 
contour  require  an  addition  of  gold  at  any  point,  place  a  small 
piece  of  the  Moss  Fibre  gold  over  the  part,  and  heat  the  inlay 
sufficiently  to  slightly  fuse  the  solder  and  attach  it.  More  Moss 
Fibre  gold  can  then  be  added  and  solder  applied  to  properly  shape 
the  part. 

The  inlay  thus  formed  is  next  trimmed  and  polished.  For 
accuracy  the  trimming  of  the  extreme  edge  is  best  done  with 
the  inlay  in  position  in  the  cavity.  A  little  of  the  gold  may  be 
removed  from  the  bottom  or  sides  of  the  inlay  with  a  small  stone 
or  a  fine  finishing  bur  operated  with  the  dental  engine,  to  provide 
a  space  for  the  cement.  When  inserted  and  cemented,  the  inlay 
resembles  a  gold  filling. 

Extensive  Restoration  of  Contour. — The  best  method  to 
practice  for  approximal  cavities  in  molars  and  bicuspids  is  as  fol- 
lows :  After  preparing  the  cavity  as  has  already 
been  described,  an  impression  is  taken  in  im- 
pression-compound and  a  plaster  model  made. 
A  piece  of  Xo.  36  gage  pure  gold  is  shaped 
first  to  the  cavity  on  the  model  and  then  to  the 
tooth  in  the  mouth.  The  gold  is  depressed  into 
any  anchorage  cavity  that  has  been  secured  at 
the  occluding  surface.  In  a  case  such  as  is 
illustrated  in  Fig.  308,  a  little  of  the  solder  is 
first  melted  in  the  most  depressed  part  of 
the  matrix  cavity  of  the  occluding  surface,  by 
holding  the  matrix  in  a  spirit  or  gas  flame. 
The  matrix  is  again  fitted  to  the  cavity  and  the 
operation  of  filling  the  cavity  with  Moss  Fibre  gold  and  solder 
as  above  described  continued  until   the  required  contour  is  ob- 


Fig.  308. 


PARTIAL  CROWN-WORK.  155 

tained.  To  facilitate  the  contouring  it  is  well  to  tack  at  the  proper 
point  a  small  globule  of  high-grade  gold  solder,  as  shown  at  A. 
To  and  around  this  globule  pack  Moss  Fibre  or  crystal  gold  or  foil 
to  the  line  or  bulge  of  the  required  contour,  and  flow  solder  in  the 
interstices,  shaping  the  rest  of  the  inlay  at  the  same  time.  If  con- 
sidered necessary,  the  matrix  may  be  invested  for  this  final  solder- 
ing. Solid  gold  inlays  made  after  the  manner  just  described  can 
occasionally  be  utilized  advantageously  to  anchor  and  support 
bridge-work. 

Solid  Gold  Tips  for  Abraded  Pulpless  Front  Teeth  in  prefer- 
ence to  fillings  are  constructed  in  the  following  manner  :   An  open- 
ing is  made  through  the  occluding  surface  of  the 
crown  into  the  root-canal.      A  flat  post,  wide  Fl^=f09' 

enough  to  fit  closely  in  the  pulp-chamber  across 
its  greatest  diameter,  thus  tending  to  pre- 
vent any  rotary  motion  of  the  gold  tip,  is  then 
formed.  A  thin  piece  of  pure  gold  plate,  about 
Xo.  30  gage,  is  adapted  and  burnished,  with 
hand-burnishers  and  Herbst's  revolving  agate 
points,  into  all  the  irregularities  of  the  abraded  surface,  and  into 
the  orifice  of  the  pulp-chamber.  The  gold  is  then  trimmed  flush 
and  even  to  the  edges,  and  burnished  just  over  them.  An  opening 
is  next  made  in  this  gold  cap,  and  through  it  the  post  is  inserted  in 
position,  fastened  with  wax,  removed,  and  soldered  to  the  cap. 
The  post  and  cap  are  inserted  in  position  and  the  end  of  the  post 
cut  off  to  about  the  length  the  gold  tip  will  need  to  be  and  the 
gold  again  burnished  to  the  edges  of  the  tooth  and  trimmed 
closely. 

Wax  cement  is  then  placed  on  the  gold  and  shaped  to  the 
exact  form  of  the  required  gold  tip.  This  is  next  encircled 
with  a  strip  of  Xo.  60  gold  foil  fitted  against  the  surface  of  the 
wax,  except,  at  the  incisal  edge,  and  extending  slightly  over  on 
the  surface  of  the  enamel  of  the  tooth.  This  foil  is  to  form  a 
matrix.  All  is  now  removed  and  invested  in  finely  calcined  mar- 
ble-dust and  plaster.     (See  Fig.  309.) 

The  investment  is  next  heated,  and  20-carat  gold  solder  melted 
into  the  matrix  formed  by  the  foil  encircling  the  cap.  The  surplus 
gold  is  then  trimmed  to  the  edge  of  the  abraded  surface  of  the 
tooth  and  to  the  desired  form  for  the  tip,  and  polished.  The 
trimming  or  polishing  of  that  portion  of  the  tip  at  or  adjacent  to 

12 


156 


CROWN-,   BRIDGE-,  AND   PORCELAIN-WORK. 


Fig.  311. 


the  edge  which  fits  against  the  tooth  should  always  be  done  with 
Fig.  310.  ^ie  **P  "*  Position  on  the  tooth.  When  finished,  the  gold 
tip  is  cemented  in  position  with  a  thin  mixture  of  oxy- 
phosphate.  Fig.  310  gives  a  sectional  view  of  a  central 
incisor  tipped  in  this  manner. 

Gold  Tips  in  Cases  of  Living  Pulps. — In  these  cases 
two  or  three  small  platinum  pins,  as  the  case  may  suggest, 
are  used  in  holes  drilled  about  the  pulp-chamber,  in  the 
manner  shown  in  Fig.  311.  Three  pins  are  generally 
placed  in  upper  incisors  and  two  in  lower  incisors.  The  three  pins 
should  always  be  used  except  in  very  small  lower  incisors  where 
the  space  will  not  permit  more  than  two.  The  pins  should  be 
inserted  and  soldered  in  the  gold  plate  one 
at  a  time,  the  plate  each  time  being  ad- 
justed to  the  surface  of  the  tooth.  The 
first  pin,  if  fitted  tightly  in  the  hole  through 
the  gold,  can  be  soldered  without  investing, 
but  an  investment  should  be  made  for  the 
soldering  of  each  subsequent  pin,  as  other- 
wise the  previously  soldered  pin  or  pins  are 
apt  to  move  from  position.  The  least  pos- 
sible quantity  of  solder  should  be  used  on 
the  first  two  pins.  After  all  the  pins  have  been  soldered  in  posi- 
tion to  the  gold  cap,  it  is  adjusted  on  the  tooth  and  the  gold  very 
carefully  burnished  to  its  surface,  trimmed,  and  shaped  up  with 
wax  as  previously  described.  A  final  investment  is  then  made 
and  the  required  form  of  the  incisal  edge  of  the  tooth  added  with 
solder. 

In  a  case  with  a  vital  pulp,  or  in  a  pulpless  tooth  if  the  gold 
tip  required  is  short,  the  ends  of  the  pins  extending  above  the  cap 
will  hold  and  maintain  enough  solder  in  position  to  give  material 
for  proper  contouring,  without  enveloping  the  wax  with  a  matrix 
of  gold  foil. 

Another  method1  of  building  the  invested  and  fitted  cap  to  the 
required  length  is :  Roll  down  a  piece  of  solder  very  thin,  about 
No.  34  or  35  gage,  cut  it  to  the  size  of  the  tip,  and  punch  holes  in 
it  for  the  pins  to  protrude  through.  Next  cut  a  piece  of  20-  or  22- 
carat  gold  plate  to  at  least  the  size  of  the  cap  and  punch  holes  in 


1  Dr.   F.  Milton   Smith's  method. 


PARTIAL  CROWN-WORK. 


157 


it  for  the  pins  in  the  same  manner  as  for  the  solder.  Place  the 
solder  on  the  cap  and  the  plate  over  the  solder,  and  apply  the 
broad  flame  of  the  blowpipe.  When  the  solder  melts,  the  piece  of 
plate  will  settle  into  position.  If  one  piece  of  plate  does  not  give 
sufficient  length  to  the  tip,  attach  another  layer  of  both  solder  and 
plate.  When  extreme  hardness  is  required,  use  clasp-gold  instead 
of  plate.  If  three  pins  are  used,  it  is  very  seldom  necessary  for 
stability  to  extend  the  plate  beyond  the  incisal  surface,  over  the 
palatal  side  of  the  tooth. 

Cases  of  Extensive  Restoration.- — Eestoration  in  gold  of  a 
crown  having  a  vital  pulp  by  the  methods  explained,  is  shown 
in  detail  by  Fig.  31 2,1  2  which  illustrates  the  partial  restoration  of 

Fig.  312. 


a  central  incisor  and  molar,  both  still  vital.  The  gold  for  the 
incisor,  it  will  be  seen,  is  adapted  to  the  palatal  surface  and  sup- 
ported by  three  pins. 

Fig.  313  shows  the  details  of  a  restoration  cast  filling  for  a 
molar.  The  contour  of  the  part  to  be  restored  was  shaped  in  wax 
on  the  cap  and  pins.  The  wax  was  covered  with  Xo.  60  gold 
foil  except  at  one  end,  and  invested  in  the  form  of  a  matrix  as 
shown  at  A,  and  in  section  at  B.  The  wax  was  removed  from 
the  matrix  through  the  open  end  with  boiling  water,  and  the 
matrix  was  heated  and  properly  filled  with  gold  solder  through 
the  same  opening. 


1  An  experience  of  several  years  in  the  use  of  gold  tips  as  described  shows 
that  they  are  much  to  be  preferred  to  tips  formed  of  gold  foil,  even  by  the 
very  best  operators,  the  alloyed  gold  being  superior  to  pure  gold  in  resisting 
attrition.— G.  E. 

-  Dr.  C.  L.  Alexander. 


158 


CROWN-,  BRIDGE-,  AND    PORCELAIN-WORK, 


Another  method  is,  after  the  cap  or  matrix  has  been  made  and 
fitted  to  the  surface  of  the  tooth,  to  shape  up  the  grinding-surface 
with  wax,  from  which  make  a  die  and  strike  up  a  cap  of  pure  gold, 
about  JSTo.  34  gage.  Fit  the  cap  over  the  wax  and  adjust  in  the 
mouth  to  determine  occlusion,  remove,  and  invest.  Leave  an 
opening  at  one  end,  and  in  large  cases  at  both  ends,  into  which  to 
melt  solder. 

Fig.  313. 


Porcelain  and  Gold. — The  restoration  of  an  extensive  fracture 
of  an  incisor  crown  with  porcelain  and  gold,  such  as  is  shown  in 
Fig.  314,  may  be  accomplished  as  here  described:  The  edges 
of  the  crown  to  form  the  joining  with  the  porcelain  are  trimmed 
straight  and  level,  and  then  polished.  A  shallow  groove  is  gener- 
ally formed  to  advantage  at  A,  Fig.  315.  A  very  thin  piece  of 
platinum  is  then  adapted  to  the  crown,  as  shown  at  B,  Fig.  316. 


Fig.  314. 


Fig.  315.  Fig.  3lfi. 


C-1 


Fig.  317. 


Fig.  318. 


n 


The  pin  C  is  fitted  to  the  root-canal,  passing  through  the  platinum. 
The  post  and  cap  of  platinum  are  then  attached  with  wax,  re- 
moved, invested,  and  soldered  with  pure  gold.  A  little  of  the  gold 
at  the  same  time  is  flowed  over  the  cap.  The  cap  and  post  are  then 
adjusted  to  the  crown,  and  the  cap  is  trimmed  level  and  bur- 
nished closely  against  the  surface  of  the  portion  to  be  restored 


PARTIAL  CROWN-WORK.  159 

and  into  the  groove  at  A,  Fig.  315.  At  this  stage  of  the  work,  to 
facilitate  the  subsequent  operations,  an  impression  can  be  taken 
which  will  remove  in  it  the  cap,  and  from  this  a  model  can  be 
made.  A  cross-pin  porcelain  tooth  is  then  ground  down  to  a  size 
and  shape  that  will  properly  restore  the  part  and  form  an  accurate 
joint  with  the  labial  edge  of  the  natural  crown,  at  which  point  the 
platinum  should  be  removed  and  the  edge  beveled  off  so  that  the 
porcelain  shall  rest  directly  against  the  tooth-structure.  The 
porcelain  is  then  backed,  cemented  to  the  cap,  removed,  and  sol- 
dered with  20-carat  solder.  The  partial  crown  when  properly 
finished  is  cemented  in  position  with  oxyphosphate. 

Fig.  317  illustrates  a  fractured  central  incisor  in  which  the  pulp 
was  not  exposed,  restored  with  a  short  piece  of  a  porcelain  tooth 
soldered  to  the  cap.  The  cap  to  the  fractured  part  was  fastened 
by  three  small  pins,  as  shown  in  Fig.  31S,  which  illustrates  the 
details  of  the  construction.  Operations  for  the  restoration  of 
teeth,  such  as  is  here  described,  are  generally  now  preferably  per- 
formed entirely  in  porcelain. 


CHAPTER    XV. 

Processes  Connected  with  Crown-  and  Bridge-Work. 

correction  of  excess  of  solder — to  securely  attach  a  crown 
— importance  of  removal  of  flux  from  interior  of  crowns 
—finishing  and  polishing. 

Correction  of  Excess  of  Solder. — To  correct  the  accidental 
presence  of  solder  on  the  inside  of  a  crown  which  interferes  with 
its  adjustment,  make  a  thin  paste  of  rouge  and  oil.  To  determine 
exactly  at  what  point  the  gold  strikes,  twist  a  wisp  of  cotton  tightly 
on  the  point  of  an  instrument  and  with  it  paint  the  natural  tooth 
with  the  paste  and  place  the  crown  upon  it.  The  interfering  spot 
will  be  exactly  marked  on  the  gold.  This  should  be  trimmed 
with  a  small  corundum-point,  and  the  crown  again  inserted  to 
determine  whether  enough  has  been  removed.  If  preferred,  the 
paste  can  be  placed  on  the  inside  of  the  gold  crown.  In  this  way 
the  interfering  point  will  be  marked  on  the  natural  tooth,  which 
can  then  be  trimmed  instead  of  the  gold  to  permit  proper  adjust- 
ment. 

To  Securely  Attach  a  Crown. — If  the  tooth  is  short,  and  the 

occlusion  of  a  character  requiring  the  reduction  of  the  collar  to 

such  a  degree  as  to  suggest  insecuritv  when 
Fig  319      Fig.  320.  . 

the  crown  is   cemented,  a  barbed  or  headed 

pin,  which  will  anchor  in  the  natural  crown 

or    root,    should   be   soldered   in   the   center 

of  the  gold  crown,   as  shown  in   Fig.    319. 

This  is  done  by  passing  the  pin  through  a  hole 

drilled  in  the  occluding  surface  of  the  crown, 

which  is  then  adjusted  in  the  mouth,  removed,  invested,  and  the 

pin  soldered  from  the  outside. 

In  the  case  of  a  seamless  crown,  if  the  pin  is  tapered  and  fitted 

tightly  to  the  hole  (Fig.  320),  the  soldering  can  be  accomplished 

without  investing,  by  holding  the  crown  and  pin  with  solder  in 

position  in  an  alcohol  flame. 
160 


PROCESSES  IN  GROWN-  AND  BRIDGE-WORK.  \Ql 

Importance  of  Removal  of  Flux  from  Interior  of  Crowns. — 

Always  boil  a  crown  in  acid  to  remove  the  flux.  The  removal 
of  flux  from  the  inner  surface  of  the  crown  is  absolutely  necessary 
if  it  is  intended  to  use  it  in  bridge-work,  as  solder  will  have  to  be 
melted  on  the  outside. 

Finishing  and  Polishing  Crown=Work. — Before  the  finishing 
the  gold  should  first  be  properly  shaped,  which  includes  trim- 
ming the  collar  off  to  a  feather  edge  where  it  fits  under  the  gum, 
so  that  the  seam  of  the  union  with  the  root  will  be  imperceptible. 
The  gold  that  has  been  placed  on  the  incisal  edge  of  the  incisor 
and  cuspid  crowns  should  be  trimmed  away,  so  that  although  it 
will  protect  the  porcelain,  very  little  if  any  gold  will  be  seen 
when  the  crown  is  in  position  in  the  mouth. 

The  preparatory  or  preliminary  dressing  off  of  the  gold  should 
be  done  with  small  corundum  or  Gem  wheels  and  points,  first 
coarse,  then  fine,  on  the  dental  engine,  which,  for  this  part  of  the 
work,  are  preferable  to  files  or  the  lathe.  Gem  wheels  may  be  used 
dry  when  desired.  This  is  an  advantage  in  trimming  certain  parts 
of  the  metal,  as  corundum  must  be  kept  wet.  The  cutting  prop- 
erty of  carborundum  for  the  purpose  is  not  superior  to  that  of  good 
corundum.  Besides  carborundum,  as  it  is  disintegrated  in  the 
grinding,  leaves  a  black  sediment  that  obscures  the  work  and 
invades  the  interstices.  In  the  final  finishing  use  fine  pumice  with 
leather  polishing-wheels  on  the  engine,  or  felt  wheels  on  the  lathe ; 
and,  in  the  polishing,  a  brush  wheel,  with  whiting  and  rouge  on 
the  lathe.  The  end  of  a  short  stick  of  soft  wood  loosely  fitting 
the  interior  of  a  gold  crown  may  be  used  to  assist  in  holding  it 
while  polishing  with  the  lathe. 

Insertion  and  Cementation. — In  the  insertion  and  cementa- 
tion of  all  crown-  and  bridge-work,  the  object  to  be  effected  is  the 
same  in  principle;  that  is,  to  form  with  an  insoluble  material  a 
solid,  substantial,  and  impervious  union  between  the  natural  tooth 
or  root  and  the  artificial  crown. 


CHAPTER   XVI. 

Cementation  of  Crown-  and  Bridge-Work. 

zinc  oxyphosphate— method  op  mixing— application— oxyphos- 
phate  with  partial  application  of  gutta-percha — cemen- 
tation with  gutta-percha— dowel  crowns— collar  crowns 
— gutta-percha  cement — advantages — method  of  using — 
method  of  measuring  the  cement— to  provide  for  surplus 
cement— requirements  for  success— oxyphosphate  in  com- 
bination with  gutta-percha  cement— amalgam. 

Zinc  Oxyphosphate. 

As  a  cement  for  effecting  the  proper  union  between  the  natural 
tooth  or  root  and  the  artificial  crown,  the  zinc  oxyphosphate 
is  generally  preferred,  and  is  in  many  respects  one  of  the  most 
suitable  that  has  as  yet  been  found.  If  at  all  exposed,  even  the 
best  preparations  are  slowly  soluble  in  the  mouth,  and  the  porosity 
of  the  compound  permits  it  to  absorb  gases  and  fluids  and  gradu- 
ally become  septic.  Exact  scientific  proportions  of  the  chemical 
substances  of  which  the  cement  is  composed  are  essential  in  its 
preparation.  The  zinc  oxid  should  be  calcined  at  a  high  heat, 
and  then  ground  to  an  impalpable  powder.  It  should  possess 
the  property  of  being  uniformly  dense  and  hard  clear  through 
the  center,  when  set,  after  being  mixed  thin  and  formed  in  a  mass. 
The  density  of  one  preparation  of  zinc  oxyphosphate  in  compari- 
son with  another  can  be  tested  by  placing  samples  of  each  of 
the  same  size,  mixed  under  similar  conditions,  in  red  ink.  After 
immersion  for  one  or  more  weeks  the  samples  can  be  removed, 
washed,  then  cut  through  the  center,  and  their  comparative  den- 
sity determined  approximately  by  the  depth  of  the  stain. 

The  setting  of  the  best  preparations  of  pure  zinc  oxyphosphate 
is  materially  affected  by  temperature.  Thus,  a  cement  which 
is  slow-setting  at  40°  F.  is  apt  to  be  quite  quick-setting  at  80°  F. 
In  some  of  the  preparations  of  cement,  an  effort  is  made  to  remedy 
this  variation  by  adulterating  with  various  substances,  but  this 
tends  to  increase  the  solubility  of  the  compound.  A  standard 
162 


CEMENTATION  OF  CROWN-  AND  BRIDGE-WORK.  163 

preparation  of  cement,  answering  the  requirements  previously 
outlined,  should  be  used  in  crown-  and  bridge-work. 

Method  of  Mixing — For  all  styles  of  crowns  with  collars,  and 
for  bridge-work  depending  on  crowns  of  similar  construction,  the 
cement  should  be  mixed  to  the  consistence  of  a  very  thick  cream; 
but  for  crowns  without  a  collar  or  ferrule  it  can  be  moderately 
thick.  For  mixing  the  cement,  a  piece  of  plate-glass  about  5 
inches  long  and  3  inches  wide  as  a  slab,  and  a  small  spatula, 
are  suitable.  The  surface  of  the  slab  must  be  perfectly  clean. 
The  acid  and  powder  should  first  be  separately  placed  on  the  glass, 
the  amount  of  powder  being  fully  equal  to  the  requirements  of 
the  acid.  A  portion  of  the  powder  should  be  drawn  over  and 
mixed  with  the  acid,  and  then  more  of  the  powder  added,  a  little 
at  a  time,  until  a  suitable  consistence  is  reached,  when  the  surplus 
powder  should  be  instantly  thrown  off  the  slab,  and  the  mixing, 
which  must  be  rapid  and  thorough,  continued.  It  is  not  a  good 
plan  to  mix  cement  excessively  thin,  and  then  wait  until  it  becomes 
thickened  by  the  process  of  setting  to  a  consistence  suitable  for 
use.  The  resulting  compound  is  unnecessarily  acid,  the  overplus 
of  acidity  being  proportioned  to  the  excess  of  acid  used  over  the 
quantity  required,  and  its  character  as  a  cement  impaired.  On 
the  other  hand,  if  mixed  too  .thick,  force  is  required  to  bring  the 
crown  or  cap  to  position,  and  the  thin  edges  of  collars  are  liable  to 
be  sprung  from  the  sides  of  the  roots;  neither  will  the  cement  ad- 
here with  such  tenacity  to  the  parts  as  when  mixed  at  a  proper 
consistence.  If  the  slab  is  placed  on  a  towel  which  has  been 
saturated  with  ice-water,  the  cold  will  retard  the  setting,  which 
is  quite  an  advantage  in  many  cases,  especially  in  the  use  of  some 
preparations  of  oxyphosphate.  In  this  respect  the  side  of  a  square 
bottle  filled  with  ice-water  and  well  corked  has  its  advantages  as 
a  mixing  slab  in  hot  weather. 

Application — The  parts  to  be  crowned  should  be  previously 
syringed  with  water  and  hydrogen  dioxid  if  the  gum-margins 
are  slightly  lacerated,  then  protected  by  a  napkin,  bathed  with 
alcohol  applied  on  cotton  with  tweezers,  and  dried  with  absorbent 
cotton  or  bibulous  paper.  In  cases  where  the  prepared  teeth  or 
roots  have  been  exposed  to  the  action  of  the  secretions  of  the 
mouth  for  one  or  more  days  during  the  construction  of  the  work, 
before  its  final  insertion,  the  surface  of  the  tooth-structure  also 
should  be  thorouo-hlv  cleaned  and  sterilized.     This  is  effectivelv 


104  CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 

done  with  fine  pumice  moistened  with  compound  tincture  of  iodin, 
applied  with  a  stick  over  the  entire  surface  of  the  tooth-structure 
and  under  the  gum-margin.  The  iodin  not  only  aids  in  cleansing 
and  sterilizing  the  parts,  but  also  acts  as  an  astringent  on  the  mem- 
brane of  the  gum. 

A  rope  of  twisted  absorbent  cotton  may  be  wound  around  each 
natural  crown  and  pressed  close  against  the  gum,  with  the  ends 
twisted  together  at  the  labial  side  so  that  the  cotton  can  be  easily 
seized  and  instantly  removed  at  the  moment  the  cement  is  ready. 
Crown-posts  may  be  slightly  barbed  or  roughened.  Collar  crowns 
should  be  inserted  and  given  a  final  burnishing.  Each  cap  or 
crown,  having  been  thoroughly  cleaned  and  dried,  is  first  filled 
with  enough  cement  to  insure  a  slight  surplus.  A  small  portion 
is  then  put  in  each  root-canal  or  hollow  part  of  a  natural  crown 
present,  and  the  artificial  crown  or  bridge  immediately  adjusted 
in  position.  In  most  cases  it  is  best  to  quickly  remove  the  napkin 
and  close  the  mouth  to  insure  the  occlusion  of  the  teeth,  and  then 
open  the  mouth  and  replace  the  napkin.  The  crown  or  bridge 
should  be  held  under  a  slight  pressure  until  the  cement  has  set. 
For  this  purpose  a  piece  of  wood  notched  on  the  end  can  be  used 
In  setting  bicuspid  or  molar  crowns  and  in  bridge-work,  how- 
ever, it  is  better  in  the  great  majority  of  cases  to  occlude  the 
teeth,  and  keep  them  in  position  under  a  steady  pressure  until 
the  cement  sets.  Under  these  circumstances  the  saliva  can  reach 
only  the  surplus  portion  of  the  cement,  and  cannot  interfere  with 
that  under  the  cap  or  crown.  One  or  two  thicknesses  of  tin  foil, 
placed  over  the  crown  as  the  teeth  are  occluded,  will  slightly  favor 
the  length. 

When  the  cement  has  set  perfectly  hard,  and  not  before,  the 
surplus  around  the  edges  should  be  removed.  In  collar  or  shell 
crowns  the  extreme  edges  of  the  gold  of  the  collar  or  shell  should 
be  given  a  final  burnishing.  Excessive  burnishing  and  force, 
though,  should  be  avoided,  as  tending  to  injure  the  cement  under 
the  collar.  Wet  floss  silk  or  dental  fiber,  charged  with  pumice, 
should  be  passed  between  and  around  the  teeth  to  remove  every 
particle  of  the  superfluous  cement,  and  finally  the  parts  should  be 
syringed  with  tepid  water. 

The  patient  should  be  requested  to  call  in  a  few  days,  so  that 
an  examination  may  be  made  to  see  if  any  particles  of  the  cement 
were  overlooked.     Cleansing  gently  at  this  time  facilitates  the 


CEMENTATION  OF  CROWN-  AXD  BRIDGE  WORK.  K35 

healing  of  the  gum  around  the  collar  or  neck.  Care  in  these 
little  details  tends  to  prevent  that  inflamed  appearance  and  reces- 
sion of  the  gum  often  seen  around  crowns,  and  also  insures  a 
satisfactory  result  to  the  patient  and  commendation  to  the  dentist. 

Oxyphosphate  with  Partial  Application  of  Gutta=Percha. — 
Previous  to  insertion  the  posts  of  crowns  should  be  slightly  barbed. 
By  incasing  the  post  with  a  film  of  gutta-percha  it  is  made  easily 
removable,  which  is  a  desirable  feature  in  crown-  or  bridge-work. 
This  is  done  by  warming  the  whole  crown  enough  to  heat  the  post, 
and  then  painting  the  post  with  a  thin  coat  of  chloro-gutta-percha. 
The  heat  instantly  evaporates  the  chloroform,  leaving  a  thin  film 
of  warm  gutta-percha  adhering  to  the  post.  The  crown  is  then  in- 
stantly placed  on  the  root  and  removed.  This  defines  the  relations 
of  the  gutta-percha  on  the  post  to  the  walls  of  the  canal,  and  indi- 
cates any  slight  surplus  if  present.  Cementation  with  the  zinc  oxy- 
phosphate completes  the  operation.  At  any  time,  by  warming  the 
crown,  the  thin  sheath  of  gutta-percha  is  softened  and  the  attach- 
ment of  the  post  may  be  easily  broken.  This  method  of  setting 
the  post  makes  bridge-work,  so  supported,  more  easily  detachable. 
A  film  of  gutta-percha  placed  in  the  grinding-surface  or  on  the 
sides  of  a  gold  cap  will  also  provide  a  similar  advantage  in  case  of 
a  gold  crown.  The  gold  cap  should  be  first  heated,  the  gutta- 
percha inserted,  and  the  cap  adjusted  and  removed  and  the  amount 
and  position  of  gutta-percha  exactly  determined.  The  cementa- 
tion is  then  conducted  as  without  the  gutta-percha.  In  all-gold 
cap-crowns  a  vent  for  the  escape  of  air  and  surplus  cement  is  made 
by  some  in  the  form  of  a  small  hole,  usually  in  the  deepest  fissure 
of  the  grinding-surface,  but  it  is  a  practice  that  is  now  being  gen- 
erally discarded.  "When  the  cement  has  hardened,  the  hole  must 
in  all  cases  be  closed  with  a  gold  or  amalgam  filling. 

Cementation  with  Gutta=Percha — The  merits  of  gutta-percha 
for  the  cementation  of  crown-  and  bridge-work  are :  Gutta- 
percha is  insoluble  in  the  fluids  of  the  mouth,  and  at  any  time  the 
work  can  be  removed  by  the  application  of  sufficient  heat  to  soften 
it.  To  be  able  to  remove  work  thus  easily  is  an  advantage  that  is 
apparent  without  comment.  In  comparison  with  oxyphosphate, 
gutta-percha,  although  possessing  the  advantages  of  elasticity,  lacks 
rigidity,  so  that  its  sphere  of  application  is  limited.  Of  the  ordi- 
nary preparations  of  gutta-percha,  the  pink  base-plate  is  the  most 
suitable  for  cementation  purposes,  and  can  be  manipulated  about 
as  easily  as  any  of  them. 


166 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  321. 


Post    Crowns — First   thoroughly   clean,    dry,    and    heat    the 
crown.    Paint  the  post  and  the  base  of  the  crown,  and  any  recesses 

in  the  latter,  with  a  very  thin 
solution  of  chloro-gutta-percha. 
The  heat  instantly  evaporates 
the  chloroform,  leaving  a  mere 
film  of  gutta-percha  tenaciously 
adhering  to  the  parts.  Fill  the 
recess  and  cover  the  base  of  the 
crown  with  a  perforated  disk 
of  gutta-percha,  and  press  the 
crown  to  position  on  the  root 
without  drying  it  of  the  saliva. 
Let  the  gutta-percha  cool  a 
little,  remove  crown,  and  trim 
surplus  from  edges;  wipe  out 
canal  with  chloroform,  dry  with 
cotton  and  hot-air  syringe.  Next 
place  on  the  post  or  in  the  canal 
enough  gutta-percha  to  insure  a 
very  slight  surplus,  heat  the 
crown,  ;ind  press  to  place. 

A  crown-setter,  illustrated  in 
Figs.  321  and  322,  heats  the 
crown  and  aids  in  setting  with 
gutta-percha.  Heat  the  copper 
end  sufficiently  to  soften  the 
gutta-percha,  and  place  the 
grooved  end  over  the  crown  with 
the  heated  copper  in  contact  with 
the  porcelain.  Hold  the  setter 
against  the  crown  until  the 
gutta-percha  becomes  soft,  when 
pressure  will  force  the  crown 
with  its  pin  to  its  proper  posi- 
tion. The  cooling  of  the  gutta- 
percha can  be  hastened  by  dip- 
ping the  crown-setter  in  a  tum- 
bler of  ice-water  and  holding  it 
against  the  tooth  until  it  is  cold.  When  the  gutta-percha  is  cold, 
the  surplus  is  removed  with  a   warmed  sharp  instrument,   and 


CEMENTATION  OF  CROWN-  AND  BRIDGE  ]YORK. 


167 


the  edges  smoothed  by  drawing  back  and  forth  against  them 
some  twisted  fibers  of  cotton  or  floss  silk  saturated  with  chloro- 
form. 

Collar  Crowns. — When  the  crown  to  be  cemented  has  a  collar 
or  cap,  it  is  best  to  first  apply  the  gutta-percha  only  to  the  cap  and 
adjust  the  heated  crown  on  the  root  or  tooth  while  wet  with  the 
saliva  of  the  mouth,  which  will  prevent  adhesion,  for  the  purpose 
of  measuring  the  amount  of  gutta-percha  required.  Xext  wash, 
dry,  and  reheat  the  gutta-percha  and  place  a  little  on  the  post. 
Dry  the  tooth  or  root  and  cement  the  crown  to  place.  This  is  the 
best  method  to  pursue  in  the  cementation  of  any  form  of  support- 
ing caps  for  a  bridge. 

As  to  the  amount  of  heat  that  can  be  tolerated  by  a  patient  in 
the  use  of  gutta-percha,  a  good  gage  will  be  the  fact  that  any 
heated  crown  or  bridge  that  can   be  held   in   the  fingers  of  the 

Fig.  323. 


operator  can  generally  be  inserted   without  great  discomfort  to 
the  patient. 

Gutta-Percha  Cement. 


The  cementation  of  crowns  and  bridges  with  ordinary  gutta- 
percha is  a  troublesome  operation,  and  their  removal  is  difficult, 
as  much  more  heat  will  be  required  to  soften  the  gutta-percha 
when  it  is  old  than  when  it  was  first  applied.  For  this  reason  a 
preparation  of  gutta-percha  which  Avill  soften  at  a  much  lower 
temperature  and  which  can  be  manipulated  more  like  a  cement  is 
preferable.     Gutta-percha  cement  is  of  this  character. 


168 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  324.  Fig.  325.     Fig.  32G. 


Method  of  Using  Gutta=Percha  Cement. — The  following  is 
a  description  of  the  method  of  using  gntta-percha  cement  and 
the  instruments  and  appurtenances  connected  with  it  for  cemen- 
tation of  crowns  or  bridges: 

1st.  Clean  perfectly  each  post 
and  the  inside  of  each  cap. 

2d.  Place  the  cement  heater  (Fig. 
323)  on  a  support  over  a  Bunsen 
name,  remove  the  handle,  and  heat 
until  a  drop  of  water  placed  on  the 
surface  will  instantly  boil  and  be 
evaporated.  Insert  the  handle,  re- 
move and  place  it  on  a  small  asbestos 
pad,  or  a  couple  of  instruments  laid 
crosswise  on  a  table,  and  again  re- 
move the  handle. 

3d.  Place  the  crown  or  bridge 
in  a  slot  in  the  cement  heater,  heat 
the  spatula,  and  place  the  requisite 
amount  of  cement  on  the  surface  of 
the  cement  heater,  opposite  the  slots 
marked  A,  Fig.  323.  Manipulate 
the  cement  thoroughly  with  a  hot 
spatula  (Fig.  324,  in  miniature),  and 
it  will  immediately  assume  a  plastic  consistence.  To  apply  the 
cement,  hold  the  crown  or  bridge  with  tweezers  in  the  slot  of  the 
cement  heater,  or  remove  and  hold  in  a  napkin  with  the  fingers. 
Reheat  when  necessary  and  return  it  to  the  slot  when  the  cement 
has  been  applied. 

This  cement  should  be  applied  with  the  hot  spatula  a  little  at  a 
time  and  in  quantity  only  in  very  slight  excess  of  what  is  re- 
quired, as  the  surplus  will  not  press  out  so  easily  as  oxyphosphate. 
In  the  case  of  collar  crowns  the  proper  and  simplest  method  to 
pursue  is  to  first  measure  the  amount  of  cement  required. 

Method  of  Measuring  the  Cement. — This  is  easily  done  by, 
first,  placing  only  a  little  of  the  cement  on  the  sides  of  the  in- 
terior of  the  collar  of  a  cap  or  that  of  a  gold  crown,  as  shown  in 
section  at  A  A,  Fig.  326,  adjusting  the  work  in  exact  position  in 
the  mouth  on  the  wet  natural  teeth  by  pressure  and  occlusion  of 
the  antagonizing  teeth,  and  then  instantly  removing.     The  saliva 


CEMEXTATIOX  OF  CROWX-  AXD  BRIDGE  WORK. 


169 


Fig.  328. 


Fig.  S2(). 


on  the  teeth  will  prevent  adhesion  of  the  cement.  The  surplus 
cement  on  the  sides  will  be  pushed  to  the  bottom  of  the  cap,  and 
when  the  cap  is  removed  will  show  the  impression  of  the  natural 
tooth  as  illustrated  in  Fig.  327.  Any  vacancy  at  the  point  B,  in 
the  bottom  of  the  cap,  will  very  accurately  indicate  the  deficiency. 
Xext  wash  the  saliva  out  of  the  cap  with  a  syringeful  of  water, 
rinse  with  alcohol  by  pouring  in  a  few  drops,  and  place  the  work 
on  the  cement  heater  and  wait  until  the  alcohol  has  evaporated, 
then  apply  the  required  additional  cement.  A  small, 
straight,  blunt-pointed  instrument,  such  as  a  broken 
excavator,  is  useful  to  carry  small  pieces  or  pellets  to 
the  bottom  or  corner  of  a  cap.  By  one  or  two  inser- 
tions in  the  manner  described  the  exact  amount  of 
cement  can  be  determined. 

To  Provide  for  Surplus  Cement. — ■'For  the  final 
insertion  a  slight  surplus  may  be  added.  It  should 
consist  of  a  very  small  quantity  placed  continuously 
around  the  cervical  edge  of  the  cap  or  crown,  as 
shown  at  S  S,  Figs.  328  and  329,  which  illustrate  a 
Richmond  and  an  all-gold  crown  in  section.  In  the 
case  of  the  all-gold  crown,  a  pellet  of  cement,  not 
larger  than  a  pin-head  or  a  fraction  thereof,  may  be 
additionally  placed  in  the  center  of  the  grinding-sur- 
face,  as  shown  at  P,  Fig.  329.  When  the  cervical 
edge  of  a  collar  is  to  be  burnished  over  a  projecting 
point,  a  little  of  the  cement  may  be  previously  placed  at  that  part 
on  the  surface  of  the  tooth  toward  the  cervix,  as  the  cement  in  the 
collar  is  liable  to  be  pressed  from  position  in  the  adjustment. 

In  any  form  of  crown  with  a  closely-fitting  post,  such  as  a  porce- 
lain or  Richmond  crown,  first  measure  the  amount  of  cement  re- 
quired at  the  base  or  cap  by  placing  the  cement  at  that  part,  insert- 
ing the  crown  in  the  mouth,  and  removing  before  applying  to  the 
post.  In  the  case  of  a  Richmond  crown,  first  place  the  cement  in 
the  interior  of  the  cap  on  the  sides  of  the  collar. 

As  only  a  very  small  quantity  of  cement  will  intervene  between 
a  close-fitting  post  or  metallic  cap  and  the  tooth-structure,  the 
adjustment  is  more  easily  effected  in  the  mouth  when  the  cement 
is  evenly  placed  over  the  surface. 

When  the  cement  has  been  applied,  the  crown  or  bridge  is  left 
on  the  cement  heater  until  ready  to  be  adjusted  in  the  mouth. 


170  CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 

To  Apply  Gutta=Percha  Cement  in  the  Form  of  a  Film  Over 
a  Surface,  place  a  little  of  the  cement  in  the  convexity  formed  in 
the  bottom  of  the  jar  not  containing  the  colored  cement  yon  are 
using,  add  chloroform,  mix  with  a  camel's-hair  brush,  and  apply 
the  solution  evenly  over  each  post  and  on  the  inner  surface  of  each 
metallic  cap.  Xext  place  the  crown  or  bridge  in  the  slot  of  the 
cement  heater  to  evaporate  the  chloroform  and  soften  the  cement. 
This  method  slightly  impairs  the  strength  of  the  cement.  Its 
application  is  best  confined  to  long,  close-fitting  gold  crowns  or 
posts,  or  to  the  temporary  cementation  of  work. 

4th.  Syringe  with  water  the  tooth  or  teeth  to  be  crowned, 
protect  from  saliva,  bathe  with  alcohol  applied  with  a  pellet  of 
cotton,  dry,  and  evaporate  all  moisture  with  a  hot-air  syringe. 

Xow  remove  the  crown  or  bridge  from  the  cement  heater,  and 
when  it  has  cooled  to  a  point  that  will  barely  permit  it  to  be  held 
between  the  fingers,  instantly  place  and  press  it  to  position  in 
the  mouth,  and  in  the  case  of  a  gold  crown  or  bridge  have  the 
patient  forcibly  occlude  the  teeth.  This  cement  is  very  adhesive, 
but  a  chloroform  varnish  for  the  purpose,  termed  "adhesive 
fluid,"  may  be  applied  to  the  tooth  before  the  insertion  of  the 
work  to  further  increase  this  property. 

Should  a  hollow  place  be  present  in  a  tooth,  it  should  be  first 
filled  with  a  pellet  of  the  cement.  If  the  cavity  is  shallow,  var- 
nish it  with  the  adhesive  fluid  before  inserting  the  cement. 

Should  a  crown  or  bridge  not  go  to  position  because  of  an  exces- 
sive amount  of  cement,  the  cement  will  have  to  be  again  heated. 
This  is  done  without  removing  the  work,  by  protecting  the  mem- 
branes and  applying  a  crown  heater,  as  shown  in  Fig.  325  (in 
miniature),  which  is  applicable  to  all  the  teeth,  or  in  Fig.  321,  for 
incisors  and  cuspids  exclusively.  Pressure  is  then  again  exerted. 
This  process  is  to  be  repealed  until  the  crown  or  bridge  is  brought 
to  proper  position  and  the  surplus  cement  pressed  out. 

The  cement  is  next  to  be  chilled  with  cold  water  from  a  syringe. 
Metallic  collars  are  to  be  burnished  at  the  neck.  Surplus  cement 
present  is  to  be  removed  with  the  point  of  an  exploring  instru- 
ment. 

Gutta-percha  cement  is,  to  a  certain  extent,  hardened  by  the 
application  of  cold,  but  does  not  acquire  its  greatest  density  before 
the  next  day,  when  the  surplus  can  lie  more  easily  removed. 

The   best    possible    adhesion    of   the   cement   to   metal   is   se- 


CEMENTATION  OF  CROWN-  AXD  BRIDGE-WORK.  \>j\ 

cured    by    lightly    scratching    intersecting    lines    on       FlG-  33°- 
the  posts  and  inner  surfaces  of  metallic  crowns,  in  the 
form  shown  in  Fig.  330,  with  a  fine,  sharp-pointed  in- 
strument, previous  to  the  process  of  cementation.     In 
open-face  or  shell  crowns,  this  process  applied  to  the 
inner  surface  of  a  strip  of  the  metal  traversing  the  cervical  portion 
of  the  labial  face  very  materially  aids  in  the  retention  of  the 
cement. 

Requirements  for  Success. — For  the  successful  use  of  gutta- 
percha cement,  bridge-work  must  be  properly  constructed.   Porce- 
lain  or  Richmond   crowns  should    have   long,   substantial   posts, 
either  round  or  of  the  Logan  pattern,  properly  fitted  to  the  canal. 
(See  Fig.  331.)    If  the  canal  is  enlarged  from  some  cause,  or  of  an 
irregular  form,  after  closing  the  foramen  with  gutta-percha,  taper 
the  end  of  the  post  and  fit  the  point  deeply  in  the  canal.     Fill  the 
canal  with  a  thin  mixture  of  Ash  &  Sons'  "Rock  Cement"  (a  zinc 
oxychlorid,  which  sets  in  two  minutes),  using  a  wisp  of  cotton 
wound  tightly  on  a  serrated  broach  to  pump  it  in  place,  insert  the 
post  and  in  thirty  seconds  withdraw  it.  wipe  off  the  film  of  cement 
adhering  to  the  surface  of  the  post,  and  reinsert  it  in  the  canal. 
Slightly  withdraw  and  reinsert  the  post  at  intervals  during  the 
remainder  of  the  two  minutes  required  for  the  setting  of  the  ce- 
ment.  Or,  varnish  the  post  with  a  thin  film  of  gutta-percha  cement 
dissolved  in  chloroform  and  evaporate  the  chloroform.     Fill  the 
canal  with  oxyphosphate  and  insert  the  post.     When  the  oxyphos- 
phate  has  set,  heat  the  post  or  crown,  withdraw  it,  and  wipe  out 
the  canal  with  a  wisp  of  cotton  saturated  with  chloro-     FlG  331 
form  to  remove  any  of  the  gutta-percha  cement  adher- 
ing in  the  canal.     Either  method  gives  a  tight-fitting 
socket  of  cement  in  which  the  post  will  fit  closely.    For 
all-gold  crowns,  badly  decayed  teeth  should  have  their 
sides    restored    with    amalgam.      Roots    should    have 
posts  or  screws  cemented  in  them  and  then  be  built  up 
with  amalgam,  as  shown  in  Figs.  39  and  40.     Short 
gold  crowns,   supporting  bridge-work,   frequently   re- 
quire one  or  two  pins  that  will  fit  in  small  holes  drilled    Fig.  332. 
in  the  deep  fissures  of  the  occluding  surfaces,  as  shown  g^pwwxm 
in  Fig.  332,  or  in  a  slot  or  cavity  in  the  side  extending  HI:*'1' 
nearly  to  the  cervical  margin  of  the  gold  crown,  as  ■*-— 
illustrated  in  section,  in  Fig.  333.     A  pin,  no  matter  how  short, 

13 


172  CROWN-,  BRIDGE-.  AND  PORCELAIN-WORK. 

inserted  in   the  center  of  the  occluding  surface  of  an  all-gold 

crown,  always  steadies  the  crown,  and  in  that  way  assists  in  its 

retention.      A  gold  crown,  the  labial  face  of  which 

has  been  entirely  removed,  should  have  pins  of  plati- 

nnnm  inserted  in  cavities  or  slots,  on  one  or  both 
of  the  approximal  sides,  as  shown  in  Fig.  405.  Roll- 
ing the  wire  under  the  flat  side  of  a  file  before  using 
in  the  construction  will  roughen  it  and  offer  a  better  surface 
for  the  adhesion  of  the  cement.  Partial  caps  on  bicuspids,  cen- 
trals, or  cuspids  are  well  secured  in  this  manner,  or  by  the  use  of 
the  Carmichael  and  the  "Staple  Crown"  described  on  page  213. 

Gold  crowns  inserted  with  gutta-percha  cement  can  be  bur- 
nished in  at  the  neck  without  injury  to  the  cement,  which  is  not 
the  case  in  the  use  of  oxyphosphate.  This  property  in  gutta- 
percha cement  will  be  found  of  great  advantage,  where  the.  con- 
tour of  a  tooth,  for  instance,  used  as  an  abutment  for  bridge-work, 
has  not  been  reduced  to  the  circumference  of  the  neck.  All-gold 
crowns  in  such  cases  should  be  made  of  soft  gold  plate,  or  plati- 
nized gold.  The  collar  can  be  stiffened,  where  considered  neces- 
sary for  rigidity,  with  solder  around  the  sides,  toward  the  occlud- 
ing surface,  and  the  metal  then  tapered  off  gradually  toward  the 
edge.  A  gold  crown,  by  being  burnished  inward  around  the  neck 
of  a  natural  tooth,  is  additionally  secured,  and  no  matter  how 
short  a  crown,  very  seldom  requires  the  aid  of  a  post  or  pins  for 
the  purpose  of  retention. 

Favored  by  proper  construction,  over  90  per  cent,  of  cases  of 
bridge-work  can  be  reliably  cemented  with  gutta-percha  cement. 
Among  the  exceptions  are  very  short  caps  or  open-face  crowns, 
in  which  pins  or  posts  cannot  well  be  inserted,  and  which,  in  sup- 
porting bridge-work,  are  subjected  to  a  great  strain. 

Oxyphosphate  in  Combination  with  Gutta=Percha  Cement. 
— Gutta-percha  cement  may  be  used  in  combination  with  oxy- 
phosphate by  applying  the  gutta-percha  cement  somewhat  scan- 
tily, and,  in  the  final  insertion  of  the  work,  coating  the  natural 
crowms  or  roots  with  a  thin  mixture  of  oxyphosphate  instead  of 
using  the  adhesive  fluid.  This  method  will  result  in  the  presence 
of  a  film  of  oxyphosphate  and  a  very  large  proportion  of  gutta- 
percha cement.  It  will  increase  the  security  of  attachment  while 
the  proportion  of  oxphosphate  present  will  not  be  enough  to  inter- 
fere with  removal.     The  inherent  weakness  of  gutta-percha  as  a 


CEMENTATION  OF  CROWS'-  AXD  BRIDGE-WORK.  173 

cement  lies  in  its  lack  of  adhesion  to  tooth-structure.  This  com- 
bination overcomes  this  objection. 

For  the  removal  of  crowns  and  bridges  cemented  with  gutta- 
percha, see  Part  III,  Chapter  IX. 

Amalgam. — Amalgam  is  but  seldom  used  to  support  and  retain 
porcelain  crowns.  Where  it  is  desirable  to  use  amalgam,  Dr. 
Kirk  gives  copper  amalgam  the  preference  as  an  attachment  for 
the  Logan  crown  to  weak  or  badly-decayed  roots.  The  foHowing 
is  Dr.  Kirk's  method  for  the  adjustment  of  Logan  and  similar 
classes  of  crowns,  which  he  has  found  satisfactory  in  those  extreme 
cases  where  there  has  been  much  loss  of  root-structure  through 
the  action  of  caries  in  the  root-canal,  resulting  in  a  large  funnel- 
shaped  opening  with  more  or  less  weakened  root-walls. 

The  canal  is  prepared  by  removing  the  softened  structure,  fill- 
ing the  apex,  and  making  suitable  undercuts  or  roughnesses  along 
its  walls,  and  then  filled  flush  with  its  orifice  with  a  good  grade 
of  copper  amalgam  softened  to  a  plastic,  buttery  condition.  The 
apical  end  of  the  crown-pin  is  sharpened  to  a  point  or  hatchet 
edge  as  may  be  most  expedient,  and  placed  against  the  amalgam 
surface  in  the  root-opening,  and  the  crown  at  once  driven  to  place 
in  close  contact  with  the  root  by  holding  against  its  morsal  (oc- 
clusal) surface  a  suitable  point  mounted  in  the  engine-mallet. 
For  this  purpose,  the  blow  of  the  mallet  should  be  considerably 
increased  in  intensity  beyond  that  ordinarily  used  for  filling- 
operations.  The  point  used  in  the  mallet  for  driving  the  crown 
home  is  best  improvised  from  a  porte-polisher  armed  with  a 
hickory  point,  the  use  of  which  avoids  chipping  the  porcelain. 
All  excess  of  copper  amalgam  is  by  this  means  driven  out  between 
the  contact  surfaces  of  the  crown  and  root  in  precisely  the  same 
manner  as  occurs  in  the  use  of  oxyphosphate.  An  excess  should 
be  used  in  order  to  be  sure  of  filling  all  interstices.  This  method, 
involving  the  use  of  copper  amalgam,  is  advocated  only  in  the 
class  of  cases  described,  for  which  it  possesses  the  advantage  of 
giving  complete  support  to  the  root,  because  of  the  great  strength 
and  insolubility  of  the  material  employed.  Other  amalgams  ex- 
perimented with  for  this  purpose  have  not  been  so  satisfactory, 
because  of  their  lack  of  plasticity,  and  of  the  flowing  quality 
which  characterizes  the  copper  amalgam  when  subjected  to  the 
rapid  vibratory  percussive  force  of  the  engine-mallet  blow. 


PART  III 


BRIDGE  WORK. 


175 


PART    III. 


brum;  k-  wo  rk. 

ANTIQUITY  OF— PRIMITIVE  METHODS  MODERN  LITERATURE  MODERN 
METHODS  ADVANTAGES  OBJECTIONABLE  FEATURES  IMPARTIAL 
CONSIDERATION. 

Antiquity  of — The  artificial  replacemenl  of  the  loss  of  a  por- 
tion of  the  te<  th  by  bridging  the  ?acan1  spaces  with  substitutes, 
supported  in  position  by  means  of  their  attachment  to  adjoining 
or  intervening  Datura!  teeth,  is,  as  we  have  seen  in  the  introduc- 
tion, of  ancient  origin,  having  been  practiced  long  before  plates 
came  into  use. 


Fig.  334. 


Fig.  335. 


Primitive  Methods. — Originally,  the  application  and  mechani- 
cal construction  of  such  dentures  was  of  a  most  primitive  charac- 
ter; and  as  the  attachments  were  -imply  Ligatures  or  clasps  of 
gold,     the     teeth     were     more 
ornamental  than  useful.     Figs.  FlG-  33G- 

334,  335,  and  336  illustrate  the 
antique  methods.1  Fig.  33  I  is 
an  illustration  of  a  specimen  of 
ancient  Phoenician  dentistry. 
Fig.  335  is  that  of  one  in  the 
Etruscan  age,  dating  about  five 
hundred  years  B.C.  Fig.  336  gives  a  view  of  the  same  denture 
inverted. 


lSee  Independent  Practitioner,  vols,  vi  and  vii.  "Evidences  of  Prehistoric 
Dentistry."  by  J.  G.  Van  Marter,  D.D.S..  Rome.  Italy.  Figs.  334,  335,  330 
are  copies  of  the  illustrations  of  the  specimens,  the  first  of  which  is  repre- 
sented as  being  in  the  museum  of  the  Louvre.  Paris,  France,  and  the  second 
in  the  Corneto  Museum,  Corneto.  Italy. 

177 


178 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


Dentures  constructed  on  the  bridging  plan  by  various  methods 
have  been  occasionally  employed  from  the  earliest  days  of  modern 
dentistry,  though  until  recent  years  the  system  has  not  obtained 
general  recognition  nor  been  extensively  practiced. 

Modern  Literature. — Dental  literature  presents  bridging  opera- 
tions as  described  by  Dubois  d'Chemant  in  1802,  J.  B.  Gariot  in 
1805,  C.  F.  Delabarre  in  1820,  Dr.  S.  S.  Fitch  in  1829,  William 
Imrie  in  1834,  J.Patterson  Clark  in  1836, and  Dr.  W.H.  Dwindle 
in  185G.  Figs.  337  and  338  are  copies  of  illustrations  in  Dr. Fitch's 
work,  published  in  New  York  in  1829,  and  Fig.  339  one  from  a 
translation  of  F.  Maury's  work  in  1813.     In  1871  the  bridging 


Fig.  337. 


Fig.  339. 


Fig.  338. 


Fig.  340. 

c    c     a.  a,   a.  c  c 


process  or  bridge  principle  was  again  brought  to  notice  by  a  patent 
applied  for  in  England  by  Dr.  B.  J.  Bing,  of  Paris,  for  an  im- 
proved means  of  supporting  and  securing  a  bridge  by  anchoring 
with  cement  or  fillings,  clasps  or  bars,  extending  from  it  into  holes 
formed  in  the  adjoining  teeth  (Fig.  340).  The  system  was  also 
practiced  in  operations  by  the  late  Dr.  M.  H.  Webb,  and  is  de- 
scribed in  his  "Notes  on  Operative  Dentistry." 

Modern  Methods. — The  facilities  afforded  by  the  artificial 
crown-work  now  in  vogue  for  supporting  and  securing  bridge  den- 
tures have  caused  a  revival  of  the  system  in  an  improved  form, 
now  termed  "Bridge-Work,"  in  which  artificial  crowns  cemented 
to  natural  teeth  or  roots  are  employed  as  abutments  to  support 


BRIDGE  WORK.  179 

artificial  teeth  which  span  or  bridge  the  spaces  between  them. 
These  bridges  are  so  devised,  in  the  best  methods,  that  while  sup- 
plying the  patient  with  the  means  of  masticating  his  food,  the 
cleanliness  of  the  denture  is  also  provided  for. 

Advantages. — Ordinarily,  bridge-work  is  immovably  cemented 
in  position.     The  claims  set  np  in  its  favor  are  as  follow- : 

First.  The  perfect  replacement  of  lost  teeth  by  artificial  ones, 
and  without  the  use  of  a  plate. 

Second.  The  absence  of  any  mechanical  contrivance  to  inter- 
fere with  the  tongue  in  articulation. 

Third.  The  natural  teeth  are  not  abraded  by  the  presence  of 
clasps,  the  functions  of  the  sense  of  taste  are  more  perfectly  per- 
formed, and  a  healthy  condition  of  the  tissues  preserved,  because 
the  gums  and  palate  are  no1  covered  over  with  a  plate. 

Fourth.  The  solidity  and  immovability  of  the  denture  at  all 
times,  both  in  speech  and  mastication. 

Fifth.  The  weight  of  the  denture  and  the  strain  of  mastica- 
tion are  proportionately  distributed  on  the  natural  teeth,  which 
are  better  suited  to  sustain  them  than  the  contiguous  alveolar  sur- 
faces. 

Sixth.  Its  special  adaptation  to  the  replacement  of  single 
teeth,  or  of  a  small  number,  where  bridge-work  is  usually  superior 
to  any  other  device. 

Seventh.  While  all  operations  performed  for  the  restoration 
of  lost  teeth,  like  other  remedial  operations,  are  temporary  rather 
than  permanent  in  their  results,  bridge-work  as  regards  perma- 
nency takes  equal  rank  with  any  other  operative  procedure. 

Objectionable  Features — The  following,  on  the  other  hand, 
are  the  objections  raised  against  bridge-work : 

First.  It  fails  to  restore  the  contour  of  the  soft  tissues  above 
the  bridge,  as  artificial  gums  cannot  properly,  in  most  cases,  be 
used  in  this  style  of  work. 

Second.  The  slots  beveled  under  the  artificial  teeth,  called 
self-cleansing  spaces,  fill  with  particles  of  food. 

Third.  The  speech  and  comfort  of  the  wearer  are  often  af- 
fected by  these  self-cleansing  slots  under  the  front  teeth. 

Fourth.  The  teeth  employed  as  abutments  are  usually  irrepar- 
ably destroyed  by  the  process  of  crowning. 

Fifth.  If  an  extensive  bridge  is  made  of  gold,  being  immov- 
able, it  is  impossible  to  keep  it  perfectly  clean,  as  the  metal  will 


ISO  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

gradually  tarnish  in  parts  out  of  reach  of  the  brush,  and  will 
gather  offensive  matter  on  its  surface  and  in  its  interstices. 

Sixth.  In  cases  where  it  becomes  necessary  to  temporarily  re- 
move the  bridge  for  the  purpose  of  repair,  or  because  of  disease 
in  the  teeth  which  support  it,  the  operation  is  difficult  and  the 
bridge  is  usually  injured  so  as  to  unfit  it  for  reinsertion. 

Seventh.  The  teeth  which  support  the  bridge  are  required  to 
bear  more  force  and  pressure  than  nature  intended, — where  the 
piece  is  large,  many  times  more, — and,  the  bridge  being  perma- 
nently attached,  at  no  time  can  any  rest  be  given  the  abutments 
or  the  contiguous  parts  by  its  temporary  removal.  Thus  in  a  piece 
of  bridge-work  of  fourteeen  teeth  supported  by  caps  or  crowns 
on  four  natural  ones,  each  one  of  the  natural  teeth  may  have  to 
bear  more  than  three  times  the  strain  in  supporting  the  weight 
of  the  denture  and  the  force  of  mastication,  that  was  intended. 
The  ultimate  result  is  evident  to  anyone  who  is  experienced  in 
dental  practice;  and  unless  the  anatomical  conditions  are  most 
favorable,  the  usefulness  and  durability  of  such  work  is  liable  to 
be  limited  in  character,  considering  the  time,  trouble,  and  great 
expense  attending  it. 

Such  are  the  objections  which  have  been  put  forth  against 
bridge-work;  and  yet,  whatever  may  be  urged  against  it,  its  ad- 
vantages have  won  from  a  majority  of  the  profession,  including 
many  accepted  authorities,  an  enthusiastic,  almost  a  sensational, 
indorsement;  some  practitioners  even  going  so  far  as  to  proclaim 
it  the  only  true  method  for  the  insertion  of  artificial  teeth. 

Impartial  Consideration — Judged  impartially,  bridge-work 
has  many  advantages  when  practiced  by  experts  who  properly  con- 
struct and  apply  it.  "Without  doubt  it  has  been,  and  is  still,  abused. 
Bridges  have  been  inserted  where  the  support  was  insufficient,  or 
the  construction  was  wrong  in  principle  or  faulty  from  lack  of 
skill.  [More  than  this:  bridge-work  has  been  passing  through  the 
experimental  period,  when  failures  are  apt  to  appear  more  promi- 
nently than  successes.  The  chronicles  of  dental  literature,  how- 
ever, in  tbi-  respect  offer  only  a  repetition  of  the  historical  diffi- 
culties that  attend  all  new  departures  in  the  arts. 


CHAP  TEE    I. 

Construction  of  Bridge-Work. 

mechanical  principles— preparation  of  the  supporting  teeth 
or  piers— construction— impressions  and  models— selec- 
tion and  adjustment  of  the  artificial  teeth— backings— 
self-cleansing  spaces— investment,  soldering,  and  finish- 
ing—warping, how  to  avoid— construction  in  sections  - 
adjustment  and  attachment — construction  of  small  pieces 
of  bridge-work. 

To  the  skilled  mechanical  dentist,  well  versed  in  metal-  and 
crown-work,  bridge-work  does  qo1  present  extreme  difficulty.  The 
foundations  or  abutments — that  is,  the  teeth  or  roots  on  which 
the  bridge  will  rest — are  first  to  be  considered,  due  respect  being 
paid  to  the  mechanical  principles  controlling  the  leverage  and  the 
force  of  occlusion  in  mastication. 

Mechanical  Principles. — The  amount  of  strain  that  can  be 
borne  by  the  different  teeth,  individually  and  collectively,  ac- 
cording to  their  position  and  condition  of  health,  should  be  care- 
fully calculated.  As  a  rule,  the  force  exerted  upon  the  incisors  in 
occlusion  will  be  directed  outward  on  the  upper,  and  inward  on 
the  lower  teeth,  and  its  tendency  Avhen  they  support  a  bridge  will 
be  to  gradually  push  them  out  of  line  in  each  direction.  When 
the  incisors  are  replaced  by  a  bridge,  the  tendency  of  the  force  of 
occlusion  is  toward  a  similar  result.  On  the  bicuspids  and  molars 
the  force  is  direct.  The  rules  which  govern  the  number  and  posi- 
tion of  the  teeth  or  roots  required  as  foundations  for  bridges  in 
practice,  are  as  follows : 

One  central  root  will  support  two  centrals,  and  if  spurs  or  bars 
from  the  sides  of  the  bridge  rest  upon  or  are  anchored  in  the  ad- 
joining teeth,  a  lateral  in  addition. 

Two  central  roots  will  support  the  four  incisors,  spurs  or  bars 

resting  on  or  anchored  in  the  cuspids  to  be  used  additionally,  if 

the  case  requires  them. 

The  cuspid  roots,  alone,  or  with  the  aid  of  a  central  root,  will 

support  the  six  anterior  teeth. 

181 


182  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

One  molar  or  bicuspid  on  one  side,  and  a  bicuspid  or  molar  on 
the  other,  with  one  or  two  roots  in  an  intermediate  position,  will 
support  a  bridge  between  them. 

One  right  and  one  left  molar,  with  the  assistance  of  the  two 
cuspids,  will  support  a  bridge  comprising  the  arch  between  them. 

A  bridge  on  one  side  of  the  mouth  can  be  supported  by  two 
or  three  teeth  or  roots  on  that  side.  The  cuspids  always  afford 
the  most  reliable  support. 

In  general,  the  application  of  these  principles  will  cover  the 
subject  of  foundations,  the  operator  being  governed  by  the  exact 
condition  of  individual  cases.  In  a  bridge  of  the  six  anterior  teeth 
on  the  two  cuspids,  when  the  articulation  of  the  antagonizing 
teeth  is  close  and  deep,  the  strain  should  be  relieved  by  an  addi- 
tional attachment  of  the  bridge  to  the  teeth  posterior  to  the  cuspids. 
This  may  be  accomplished  in  this  case,  as  well  as  in  other  dif- 
ferently located  pieces  of  bridge-work,  in  a  variety  of  ways,  the 
character  or  form  of  device  to  be  determined  by  conditions  and 
requirements  of  each  case.  The  adjoining  tooth  or  teeth  may 
be  capped  with  open-faced  gold  crowns  or  by  crowns  which  en- 
tirely envelop  the  natural  crown;  or,  a  bar  may  be  extended  into 
and  anchored  partly  across  the  occlusal  surface  of  the  additional 
supporting  tooth.  If  this  is  pulpless,  the  bar  can  be  extended  into 
the  pulp-chamber.  An  inlay  anchorage  may  also  be  utilized  for 
the  purpose  of  support.  This,  like  the  bar,  does  not  necessitate 
extensive  mutilation  of  the  form  of  the  natural  crown. 

Selection  of  the  most  suitable  teeth  as  abutments  or  piers  in 
bridge-work  operations  so  as  to  most  effectively  distribute  the 
force  of  occlusion  will  assure  the  best  practical  results,  especially 
as  regards  the  maintenance  of  stability  of  the  abutments,  on 
which  depends  the  durability  of  the  work. 

Preparation  of  the  Supporting  Teeth,  Piers,  or  Abutments. 
— The  preparation  of  teeth  or  roots  to  support  a  bridge  is  the 
same  as  for  ordinary  crowns,  except  that  the  trimming  of  the 
sides  and  the  drilling  of  the  root-canals  of  the  various  anchorages 
should  be,  as  far  as  possible,  in  parallel  lines,  so  that  the  collars 
and  posts  of  the  crowns  shall  move  readily  to  their  places  in  the 
adjustment  of  the  finished  bridge.  Teeth  or  roots  which  are  to 
be  supplied  with  porcelain-faced  or  all-gold  cap-crowns  are  crowned 
by  some  one  of  the  methods  already  described.  The  roots  which 
are  to  carry  porcelain-faced  crowns  can  be  so  crowned  or  only 


COXSTRUCTIOX  OF  BRIDGE-WORE. 


1S3 


Fig.  341. 


capped,  the  posts  being  soldered  and  allowed  to  project  a  short 
distance  beyond  the  caps. 

The  lines  of  the  crowns  of  teeth  or  root-canals  to  be  used  as 
abutments  or  supports  for  bridge-work  are  seldom  exactly  parallel. 
This  condition  should  be  borne  in  mind  and  receive  proper  con- 
sideration in  their  preparation.  "When  one  of  the  bridge  support- 
ing teeth  tips,  or  when  two  of  them  lean  toward  each  other,  the 
tipping  side  or  sides  may  require  extensive  trimming,  while  the 
other  side  or  sides  will  generally  need  proportionately  less.  Fre- 
quently a  leveling  or  straighten- 
ing of  the  contour  at  its  projecting 
point  only  will  be  necessary.  This 
is  explained  in  Fig.  341,  which  is 
supposed  to  represent  a  molar  and 
cuspid  with  living  pulps.  The 
cuspid  in  tipping  forward  lias 
straightened  the  line  of  the  pos- 
terior ofr  distal  side,  so  that  it  requires  very  little  trimming.  The 
proportion  requiring  removal  at  the  point  A  will  be  regulated  to 
some  extent  by  the  shape  given  the  molar.  By  considerable  reduc- 
tion of  the  posterior  side  of  the  molar  at  the  point  B, — to  a  line 
parallel  with  the  anterior  or  mesial  side  of  the  cuspid, — a  form  is 
given  to  both  teeth  which,  with  a  moderate  reduction  of  the  an- 
terior or  mesial  side  of  the  molar,  will  permit  proper  removal  and 
insertion  of  the  caps  in  the  construction  and  adjustment  at  the 
cervical  section  when  permanently  inserted. 

It  is  not  essential  that  the  parallel  lines  of  the  sides  of  prepared 
teeth  shall  form  a  right  angle  to  the  surface  of  the  gum  or  the 
space  between  them. 

The  application  of  this  principle  to  the  preparation  of  a  lower' 
molar    and    bicuspid    for 
an    intervening   bridge    is 
shown  in  Fig.  342,  which 
is    typical    of    cases    fre- 


Fig.  342. 


quently  presented.  Here 
straightening  of  the  pos- 
terior or  distal  side  of  the 
bicuspid  and  removal  of  a 

considerable  portion  of  the  anterior  or  mesial  side  of  the  molar,  as 
illustrated  by  the  lines,  will  secure  a  form  that  will  permit  of  the 
adjustment  of  the  caps. 


184  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

This  principle  is  further  exemplified  in  Fig.  343,  should  these 
lower  cuspids  or  the  lateral  incisor  be  used  to  support  a  bridge. 
The  presence  of  decay  on  that  side  of  a  tooth  requiring  the  most 
FlG  343  shaping  facilitates  the  operation, 

as  chisels  and  cross-cut  burs  can 
be  used  to  remove  the  main 
portion  of  the  bulging  enamel. 
The  cavity  should  be  excavated 
and  filled  with  cement,  or,  pre- 
ferably, amalgam,  previous  to  the  final  shaping. 

Plain,  thin  corundum-disks  will  remove  the  approximal  surface 
toward  an  adjoining  tooth  more  rapidly  than  those  of  vulcarbo, 
but  they  must  be  used  with  greater  precision  to  avoid  fracture. 
Commence  with  a  disk  of  moderate  circumference  and  follow  with 
larger  sizes.  Removal,  or  mutilation  of  the  contour  of  an  adjoin- 
ing tooth,  should  be  carefully  avoided.  Frequently  the  formation 
of  a  space  can  be  advantageously  commenced  with  a  thin  safe- 
sided  separating  file,  then  increased  with  paper  corundum-disks. 
These  may  be  then  followed  with  the  regular  disk.  Small,  moder- 
ately thick  corundum-wheels  or  disks,  whose  circumference  has 
been  considerably  reduced  by  use,  may  be  advantageously  used  on 
the  sides  of  the  teeth  approximal  to  the  space  to  be  bridged.  The 
reduction  of  the  labial  and  palatal  or  lingual  sides  need  only  be 
such  as  will  give  a  form  that  will  permit  the  edge  of  the  collar  of 
the  crowns  to  slide  over  the  coronal  section  and  assume  the  proper 
position  at  the  gum-margin.  The  occluding  surfaces  of  teeth  re- 
quire to  be  removed  sufficiently  to  permit  the  presence  of  an  inter- 
vening surface  of  metal  capable  of  resisting  attrition.  The  proper 
thickness  of  the  metal  for  this  purpose  is  regulated  by  the  charac- 
ter of  the  occlusion.  The  hardness  of  the  metal  to  be  used  for 
forming  the  occluding  surfaces,  whether  it  is  an  alloy  of  copper 
and  platinum  or  largely  copper,  in  contrast  to  gold  plate  such  as 
is  used  to  form  the  sides  of  the  crown,  may  also  be  considered  in 
calculating  its  resisting  power. 

The  reduction  of  sound  teeth  to  be  used  as  abutments  in  bridge- 
work  to  a  thimble-shaped  form  is  unnecessary.  Such  a  reduction 
demands  in  many  cases  the  devitalization  of  pulps  whose  vitality 
can  be  preserved,  as  a  rule,  by  the  adoption  of  less  extreme  meas- 
ures. The  removal  of  contour  so  as  to  permit  the  collar  of  a  gold 
cap  to  pass  just  under  the  free  margin  of  the  gum  is  sufficient. 


COXSTh'UCTIOy  OF  BRIDGE-WORK. 


18; 


To  pass  deeper  than  this  point  will  generally  demand  considerably 
more  reduction  of  the  coronal  section  above  it.  Figs.  311,  315. 
316,  and  317  illustrate  upper  and  lower  bicuspids  and  molars  of 
normal  form.  The  lines  indicate  as  much  as  usually  requires 
removal  in  such  cases. 

The  proportion  of  "bulging"  constituting  the  contour  of  teeth 
varies  considerably.     Short  bicuspids  and  molars  commonly  de- 


FlG.  344. 


Fig.  34.1. 


mand  less  shaping  to  prepare  them  for  the  reception  of  caps  than 
longer  teeth.  Second  and  third  molars,  when  the  gum-margin 
covers  the  coronal  section  extensively,  seldom  require  much  shap- 
ing. 

In  the  case  of  a  sound  molar  with  the  crown  fully  exposed  and 
slight  recession  of  the  gum;  a  reduction  of  the  contour  sufficient 
to  permit  a  proper  adjustment  of  the  collar  of  the  metallic  cap  at 


Fig.  34G. 


Fig.  347. 


the  neck  will  seldom  be  found  practicable  without  extirpation  of 
the  pulp. 

A  secure  anchorage  to  such  molars  and  bicuspids,  especially 
those  in  the  lower  jaw,  is  easily  obtained  by  merely  reducing  the 
contour  sufficient  to  allow  the  formation  of  a  cap  which  will  partly 
cover  the  coronal  section  and  fit  at  the  margin  as  shown  in  Fig. 
318.  One  or  two  short  pins  may  be  inserted  in  the  cap  for  addi- 
tional security  if  considered  necessary. 


186 


CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 


In  a  case  where  a  molar  tips  in  the  manner  shown  in  Fig.  349, 
the  most  advisable  plan  usually  is  to  cap  the  molar  regardless  of 
its  position,  and  place  on  the  anterior  side  of  the  crown  a  socket 
attachment  for  the  posterior  or  distal  end  of  the  bridge. 

The  presence  of  decay  with  extensive  calcification  of  the  pulp 
in  a  tooth  will  admit  of  the  removal  of  more  enamel  and  dentin 
than  if  it  were  perfectly  sound. 

When  teeth  are  pulpless,  shaping  can  be  more  freely  practiced. 
In  such  cases  the  collar  should  be  carried  well  under  the  gum- 
margin  as  a  protection  to  the  devitalized  dentin  against  decay, 
and  the  occluding  surface  may  be  more  extensively  removed. 
Extreme  reduction  of  the  coronal  section  of  a  tooth  does  not  always 
facilitate  the  work  of  construction,  frequently  rather  the  reverse, 
as  the  presence  of  a  reasonable  portion  of  the  crown  will  steady  the 
collar  or  cap  during  its  formation.     It  will  also  assist  in  its  reten- 


Fig.  34S. 


Fig.  349. 


A  A  is  the  line  to  which  the  nat- 
ural crown  may  be  removed  and  the 
gold  cap  extended. 


tion  in  correct  position  in  the  mouth  for  the  construction  of  the 
bridge-work. 

In  the  preparation  of  the  front  teeth  for  post  crowns  with 
porcelain  fronts,  when  necessary,  the  canal  may  be  reamed  a  little 
to  one  side  at  the  orifice  and  the  post  of  the  crown  correspondingly 
tapered  on  that  side  to  favor  its  insertion  in  and  removal  from  the 
canal. 

As  to  whether  an  incisor  or  cuspid  should  be  entirely  capped  with 
gold,  or  a  method  adopted  by  which  the  metal  shall  be  only  slightly 
exposed  or  entirely  invisible,  in  preference  to  excising  the  crown 
and  inserting  on  the  root  a  cap  with  a  porcelain  front,  is  a  subject 
to  be  determined  by  the  conditions  and  circumstances  of  the  case. 
The  position  and  occlusion  of  a  tooth,  its  shape  and  general  ap- 
pearance, whether  it  is  sound,— free  from  decay, — or  partially  or 
extensively  decayed,  whether  the  pulp  is  living  or  almost  entirely 


GOXUTRUGTIOX  OF  BRIDGE-WORK. 


187 


calcified  or  has  been  already  devitalized,  are  conditions,  and  the 
age  and  sex  of  the  patient  are  circnmstances,  which  should  influ- 
ence the  operator  in  the  adoption  of  the  form  of  construction. 
The  illustrations  in  succeeding  chapters  on  bridge-work  show,  by  a 
large  selection  of  cases,  numerous  methods  which  may  be  prac- 
ticed. 

A  normal  or  uniform  line  of  occlusion  of  the  teeth  favors  the 
construction  and  use  of  bridge-work.  "When  such  a  condition  does 
not  exist,  the  defect  should  be  remedied  as  much  as  possible  by 
trimming  the  incisal  edges 
and  occluding  surfaces  of 
such  teeth  as  are  out  of  line. 

Fig.  350  illustrates  a  case 
in  which  the  occlusion  is  not 
uniform.  The  dotted  line 
indicates  how  much  of  the 
various  teeth  requires  to  be 
removed  to  remedy  the  de- 
fect and  render  the  occlusion  favorable  to  the  insertion  of  bridge- 


Fig.  350. 


work.  Sometimes  the  removal  of  a  pulp  is  necessary  in  order  to 
effectively  shorten  a  tooth  which  has  become  excessively  elongated. 

Construction. — The  case  represented  in  Fig.  351  will  be  used 
to  illustrate  the  construction  of  a  piece  of  bridge-work  in  all  its 

14 


]§g  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

details.  The  abutments,  or  supports,  consist  of  the  right  second 
molar  capped  with  an  all-gold  crown,  constructed  in  sections  by 
first  forming  the  collar  and  then  soldering  on  the  cap  (see  page 
101),  the  two  cuspid  roots  capped  for  collar  crowns  with  porcelain 
fronts  (see  page  83),  and  the  left  first  molar,  which  will  afford 
anchorage  to  a  bar  on  that  side  of  the  bridge  as  shown  in  Fig. 
352.  A  slot,  dovetail  in  form,  is  usually  cut  well  into  the  body 
of  the  last-named  crown,  but  not  to  an  extent  that  will  endanger 
the  pulp  (Fig.  353).  If  the  tooth  is  not  decayed,  the  slot  may 
be  first  cut  with  a  corundum  or  vulcarbo  disk.  The  shaping  is 
best  completed  with  fissure-burs. 


Fig.  352. 


Fig.  353. 


i    \ 


Impressions  and  Models.1 — With  the  crowns  and  caps  in  posi- 
tion, an  impression  of  the  case  and  the  articulating  or  occluding 
teeth  is  then  taken  at  the  same  time  with  plaster  slightly  colored 
with  carmine,  to  which  is  added  a  little  potassium  sulfate, — less 
than  the  proportion  of  salt  generally  used, — which  causes  it  to  set 
quickly.  The  plaster  is  mixed  moderately  thick,  and  either  rolled 
in  a  mass  in  the  fingers,  which  should  be  wet  to  prevent  adhesion 


1  Impression-compound  is  used  to  some  extent  for  this  purpose  instead  of 
plaster,  but  in  the  author's  opinion  cannot  be  recommended  as  suitable. 
Dental  Lao  may  be  used  in  some  cases  for  small  impressions  (see  Part  V, 
Chapter  III). 


COXSTRUCTIOX   OF  BRIDGE-WORK. 


189 


of  the  plaster,  or  with  the  aid  of  a  spoon  is  placed  around  in  the 
mouth  on  the  crowns,  caps,  and  parts  to  be  included  in  the  bridge, 
and  the  antagonizing  teeth  occluded  tightly  and  so  held  until  the 
plaster  sets.  The  mouth  is  then  opened  and  the  plaster  carefully 
removed,  the  pieces  being  adjusted  together  should  it  break.  The 
crowns  and  caps  (the  latter  held  more  firmly  by  the  protruding 
ends  of  the  pins)  are  generally  removed  in  the  impression;  if 
not,  they  should  be  transferred  from  the  mouth  to  it.  The  plaster 
is  then  varnished  and  oiled,  and  on  the  side  containing  the  crowns 
a  model  is  run,  composed  of  one-third  calcined  marble-dust  and 
two-thirds  plaster,  in  which  a  little  potassium  sulfate  may  be 
added.  When  this  model  has  become  properly  set,  it  is  mounted 
with  plaster  on  an  articulator,  and  the  other  side  of  the  colored 
plaster  impression  giving  the  articulation  is  run  with  plaster  and 
the  opposite  section  of  the  articulator  adjusted.  When  the  im- 
pression plaster  is  removed  (an  operation  which  is  greatly  facili- 
tated by  its  having  been  colored  with  carmine),  a  correct  model 


Fig.  354. 


and  articulation  of  the  case  will  be  found,  with  the  crowns  and 
caps  in  exact  position  as  in  the  mouth  (Fig.  354).  The  surface 
of  the  model,  which  is  softer  than  one  of  pure  plaster,  is  much 
hardened  by  the  application  of  several  coats  of  thin  sandarac 
varnish. 

Another  method  is :  first  take  the  "bite"  or  impression  of  the 


190  CROWN-,  BRIDGE-,  AXD  PORCELAIX-WORK. 

occluding  teeth  in  wax  with  the  caps  and  crowns  in  position  in  the 
mouth,  and  after  that  the  impression  of  the  case  in  an  impression- 
tray  with  plaster.  When  the  model  has  been  made,  the  wax  ''bite'' 
is  then  placed  on  it  and  an  articulating  model  run  in  the  usual 
manner. 

Dr.  Melotte's  method  is  to  place  a  piece  of  impression-com- 
pound in  the  space  between  the  crowns  to  be  occupied  by  a  bridge, 
and  occlude  the  teeth.  The  compound  is  then  chilled,  removed, 
trimmed,  and  readjusted  until  it  accurately  fits  the  space,  when 
it  is  placed  in  position  and  an  impression  is  taken  with  plaster. 
When  the  impression  is  removed,  iron  pins  to  act  as  dowels  are 
placed  in  the  portions  representing  the  natural  teeth,  and  then 
several  pieces  of  fusible  metal,  by  a  few  puffs  of  flame  from  the 
blowpipe,  are  melted,  in  around  the  pins.  The  rest  of  the  impres- 
sion is  then  run  with  plaster  and  marble-dust  in  the  usual  manner. 
This  forms  a  plaster  model  on  which  the  natural  teeth  are  repre- 
sented in  metal.  These  metal  teeth  are  to  be  removed  before 
investing  in  soldering  the  bridge.  An  impression  of  the  occlud- 
ing teeth  is  taken  in  plaster,  and  the  entire  impression  run  with 
fusible  metal.  When  the  plaster  impression  is  removed  from  the 
model  of  the  bridge,  the  piece  of  impression-compound  between 
the  crowns  is  to  be  left  in  position,  and  the  metallic  model  of  the 
occluding  teeth  fitted  in  place,  guided  by  the  indentations  of  the 
occluding  teeth  in  the  compound,  and  the  case  mounted  on  an  ar- 
ticulator. The  principal  object  of  this  method  is  to  avoid  fracture 
of  forms  of  natural  teeth,  both  in  removal  from  impressions  and  in 
the  construction  of  the  bridge-work. 

Fracture  of  the  form  of  the  occluding  teeth  of  the  articulating 
model  or  "bite,"  when  made  entirely  of  plaster,  can  be  almost 

entirely  avoided  and  their 
FlG-  355-  Fig.  35G.  rem0val  from  the  plaster 

___^-— ^  /  ~"\  impression     simplified    by 

giving  them  the  shapes  il- 
lustrated in  Figs.  355  and 
356.  This  is  done  by  trim- 
ming and  shaping  the  mold 
of  the  teeth  in  the  plaster 
impression  at  the  lingual 
side  to  form  C  or  C,  after 
the  removal  of  the  impression  from  the  mouth,  and  thoroughly 


CONSTRUCTION  OF  BRlDdl.-WOllK. 


101 


Fig.  357 


varnishing  and  oiling  before  running  the  plaster.      The  shape 

given  in  no  respect  impairs  their  form  for  the  articulating  work. 

Selection  of  Artificial  Teeth  and  Formation  of  Dummies. — 

The  pins  protruding  from  the 
caps  on  the  model  are  next  cut 
off  short.  Teeth  are  selected, — 
ordinary  cross-pin  plate  teeth  for  84  =1 
the  incisors  and  cuspids,  and  par- 
tial teeth,  representing  the  front 
section  of  the  tooth  and  styled  ?a 
porcelain   facings,    which    were 


specially  designed  for  crown- 
and  bridge-work,  for  the  bicus- 
pids and  molars  (Fig.  357). 
Cuspids  are  sometimes  used  to 
form  the  fronts  for  bicuspids. 
The  teeth  are  ground  and  fitted 
to  the  model  and  articulation,  so  that  the  labial  upper  edge  of  the 
teeth  shall  press  lightly  on  the  gum.  Those  which  are  intended 
to  form  the  fronts  of  the  caps  on  the  cuspid  roots  should  be  ad- 
justed in  the  ordinary  manner  for  single  crowns.  To  determine 
the  proper  positions  of  the  teeth  for  producing  the  best  appearance, 
they  can  be  adjusted  in  the  mouth  on  wax,  without  the  gold 
crowns  or  caps  of  the  supports.  The  correct  position  of  the  teeth 
on  the  model  having  been  obtained,  investing  material,  composed 
of  one  part  plaster  to  two  of  calcined  marble-dust,  is  placed  on  the 
outside  of  the  model  on  the  labial  aspect  of  the  teeth,  merely  suffi 
cient  in  quantity  to  hold  them  in  position,  thus  forming  a  matrix, 
or,  the  matrix  can  be  formed  of  plaster  and  entirely  removed 
before  investing  for  soldering  (Fig.  358).  The  wax  is  then  re- 
moved, exposing  the  palatal  portion,  and  permitting  the  forms 
and  position  of  the  teeth  to  be  studied.  The  porcelain  teeth  or 
fronts,  with  the  exception  of  fronts  for  the  roots  capped,  are  then 
removed  from  their  investment,  and  the  base  ground  from  a  line 
on  the  palatal  side  below  the  pins,  straight  to  the  labio-cervical 
edge  (A  and  B,  Fig.  358).  This  is  to  form  the  self-cleansing 
spaces. 

Backings. — The  incisors  and  cuspids  are  backed  and  the  incisal 
edges  shaped  and  backed  so  that  they  will  be  protected  when  sol- 
dered and  finished  the  same  as  in  the  case  of  a  single  crown  as 


19  -2 


CROWN-,  BRIDGE-.  AND  PORCELAIN-WORK. 


described  on  pages  89  and  90.  The  backings,  if  preferred,  may  be 
extended  down  on  the  curve  of  the  self-cleansing  space.  A  more 
desirable  result  is  secured  if  the  backing  extends  only  to  the  edge 
of  the  self -cleansing  space,  and  the  porcelain  is  polished,  as  its  sur- 
face is  superior  in  cleanliness  to  that  of  gold.  If  the  platinum 
backing  nsed  is  so  exceedingly  thin  as  to  be  of  the  nature  of  foil, 
it  is  advisable  to  rivet  a  small  piece  of  gold  plate  over  it  on  the 
back  of  the  tooth,  to  insure  against  melting  the  platinum  off  the 
porcelain  with  the  gold  in  the  soldering,  which  is  apt  to  occur  if 


aon 


Shows  "dummies"  in  various  stages  of  construction.  A,  central  incisor,  and  B, 
bicuspid,  ready  for  metallic  backing.  C  is  a  central  backed.  D  D  D,  porcelain  fronts  as 
they  appear  on  insertion  after  the  process  of  backing,  capping,  and  soldering. 


a  pointed  name  is  directed  against  it.     The  cuspids  are  backed  in 
the  manner  described  for  collar  crowns. 

The  bicuspid  and  molar  porcelain  fronts,  their  tips  being  ground 
off  (A,  Fig.  359),  are  lined  in  a  similar  manner.  A  cap  of  pure 
gold  or  gold  lined  with  platinum,  representing  the  grinding-surface 
of  each  tooth,  is  struck  up  as  described  and  illustrated  in  the  con- 
struction of  gold  crowns  (see  page  95),  and  the  concave  portion 
tilled  by  melting  in  scraps  of  1  8-carat  gold  plate  or  hard-flowing 


CONSTRUCTION'  OF  BRIDGE-WORK. 


193 


solder.  When  22-carat  gold  is  used  to  form  the  cap  it  should  be 
filled  with  ordinary  or  hard-flowing  solder.  The  surface  is  then 
ground  smooth  (B),  and  closely  fitted  to  the  tip  of  the  porcelain 
front  to  form  the  occluding  surface  in  accordance  with  the  articu- 
lation of  the  lower  Teeth,  and  the  triangular  space  between  the 
backing  and  cap  filled  in  and  shaped  with  wax  to  the  form  shown 
in  Figs.  361  and  364.  The  metallic  occluding  surface  is  to  pro- 
tect the  porcelain.  Triangular  pieces  of  very  thin  gold  plate, 
platinum.  No.  60  gold  foil,  or  mica  (C,  Fig.  359),  cut  and  fitted 


Fig.  359. 


HPIP--B 


Fig.  3G0. 


to  the  sides,  over  which  they  should  extend  slightly,  will  retain 
the  gold  in  position  when  melted,  but  are  seldom  necessary.  The 
tooth  is  next  invested  with  the  others,  leaving  the  back  open, 
presenting  the  form  of  a  pocket  (Fig.  360). 1 

Another  method  of  constructing  bicuspid  and  molar  dummies 
is  to  fit  the  cap  to  the  buccal  edge  of  the  porcelain  front,  back  the 
porcelain  with  thin  platinum,  extending  the  backing  over  and 
between  the  porcelain  and  cap,  and  then  filling  in 
the  space  with  gold  in  soldering,  as  shown  at  A,  in 
Fig.  361. 

The  bar  intended  to  be  anchored  in  the  slot  cut 
in  the  molar  on  the  left  side  is  made  of  platinum 
wire,  about  ISTo.  15  U.  S.  standard  gage,  with  the 
end  shaped  as  shown  in  Figs.  362,  367,  and  368. 
It  may  be  fastened  with  wax  to  the  artificial  tooth 
and  adjusted  in  the  mouth  to  determine  accuracy  of  position  be- 
fore investing;. 


Fig.  361. 


1  See  the  Hollingsworth  System  for  description  of  method  of  swaging  grind- 
ing-surfaces  of  several  crowns  and  dummies  on  one  piece  of  plate. 


194  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Self=Cleansing  Spaces — The  advisability  of  constructing 
Fig  36^  bridge-work  with  what  are  termed  self-cleansing 
spaces  is  not  favorably  accepted  of  late  by  many 
practitioners.  Instead,  the  following  method  is 
adopted :  Porcelain  fronts  thicker  in  the  line  from 
the  labial  to  palatal  side  than  those  most  commonly 
used  are  selected.  The  base  or  cervical  section  of  the  porcelain  is 
ground  and  fitted  to  the  alveolar  ridge  very  exactly.  The  fronts 
are  then  waxed  in  position,  and  with  a  fine-pointed  lead-pencil 
a  line  is  drawn  accurately  around  the  base  of  each  porcelain 
front  on  the  model.  The  fronts  are  then  removed,  and  with  a 
suitable  scraper  the  plaster  under,  and  only  under,  the  base  of  each 
is  removed  uniformly  the  thickness  of  cardboard.  The  porcelains 
are  then  fitted  back  in  position  with  the  bases  in  the  indentations. 
The  work  is  then  proceeded  with  in  the  usual  manner.  When  the 
bridge  is  finished  and  inserted,  the  base  of  each  porcelain  will  uni- 
formly indent  the  gum  to  the  depth  the  plaster  was  removed. 
This  conformation  will  exclude  particles  of  food  and  present  a 
much  more  agreeable  shape  to  the  tongue  and  a  better  appearance 
for  the  patient.  The  shape  a  bicuspid  dummy  would  assume, 
constructed  as  described,  is  shown  in  Yig.  361.1 

The  teeth  forming  the  bridge  between  the  crowns  are  called 

Fig.  363.  Fig.  304. 


"dummies."  In  the  construction  of  dummies  it  is  well  to  favor 
the  occluding  surface  by  shaping  it  a  trifle  narrower  from  labial 
to  palatal  side  than  the  corresponding  natural  tooth  was,  and  for 
the  purpose  of  forming  less  of  a  slant  between  the  occluding  sur- 
face and  the  gum. 

Investment  and  Soldering. — All  the  porcelain  teeth  or  fronts 
can  be  invested  at  the  same  time,  including  the  incisors  and  porce- 


1  The  author,  at  present,  in  his  own  practice  constructs  most  of  his  work  in 
this  manner. 


COXSTh'UCTIO\  OF  BRIDGE -WORK. 


195 


lain  fronts  to  the  cuspid  crowns,  in  the  manner  shown  in  Fig.  363. 
In  the  soldering,  if  the  backing  is  done  with  platinum,  and  the 
occluding  surfaces  of  the  bicuspids  and  molars  made  with  24-carat 
gold  or  gold  lined  with  platinum,  IS  or  20-earat  gold  plate  or 
hard-flowing  solder  (Part  V,  Chapter  I)  may  be  melted  into  the 
pockets  formed  by  the  cap  and  side-pieces  to  fill  out  to  the  line 
at  A,  Fig.  364,  and  flowed  over  the  backings  of  the  incisors  and 
cuspid  fronts  in  sufficient  quantity  to  shape  them  as  shown  at  B, 
Fig.  365.  When  the  backing  and  occluding  surfaces  are  made  of 
18  or  20-carat  gold  plate,  18  or  20-carat  solder  and  small  pieces 
of  gold  plate  should  be  used.  After  the  soldering  and  removal  of 
the  borax  with  acid,  the  metal  of  each  tooth  is  very  carefully 
trimmed  and  shaped, — it  is  easily  done  at  this  time, — with  corun- 
dum-wheels and  points,  but  not  polished. 

The  teeth  are  next  placed  in  their  relative  positions  on  the 


Fig.  365. 


Fig.  36(1. 


model  as  shown  at  D  D  D,  Fig.  358,  and  attached  to  one  another 
with  wax  in  proper  relation  and  only  where  they  are  to  be  united 
with  the  gold  solder.  The  model  is  then  detached  from  the 
articulator,  trimmed  down  as  much  as  possible  in  size,  and  addi- 
tional investing  material,  composed  of  two  parts  marble-dust  and 
one  of  plaster,  or  one  part  plaster,  one  marble-dust,  and  one 
common  white  sand,  applied  until  all  of  the  bridge  is  covered  ex- 
cept the  space  along  the  backings  and  crowns  where  they  are  to  be 
united  in  the  soldering.  To  prevent  fracture  during  the  soldering 
process,  which  might  readily  occur  from  contraction  in  so  large 


196  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

an  investment,  an  iron  wire  or  a  narrow  horseshoe-shaped  strip 
of  sheet  iron  should  be  placed  in  the  investment  so  as  to  encircle 
the  teeth  and  crowns  about  one-eighth  of  an  inch  from  their 
exterior  surface  (Fig.  366).  In  any  spaces  between  the  back- 
ings pieces  of  gold  or  platinum  plate  or  wire,  about  one-eighth  of 
an  inch  long,  are  placed  lengthwise,  very  small  places  being 
packed  with  gold  foil,  and  the  joints  well  soldered.  When  the 
hackings  have  been  soldered  with  gold  plate  or  hard-flowing  solder, 
20-carat  solder  may  be  used.  If  the  backings  were  done  with  20- 
carat  solder,  an  easy-flowing  18-carat  solder  should  be  used.  The 
soldering  is  best  done  with  a  gas  blowpipe  on  a  piece  of  charcoal 
with  a  concave  depression.  (See  "Soldering,"  Part  V,  Chapter  IV.) 
When  the  bridge  is  removed  for  finishing,  the  joints  of  the  back- 
F      36-  ings    and    crowns    are    finished 

with  corundum  -  wheels  and 
points  and  leather  polishing- 
wheels  on  the  engine,  and  the 
entire  bridge  finely  polished 
with  whiting  or  rouge  carried  by 
a  brush -wheel  on  the  lathe.  Any 
little  pits  that  may  exist  can  be 
filled  in  with  gold  foil.  The 
bridge  is  then  ready  for  inser- 
tion (Fig.  367).  If  the  con- 
structive details  have  been  prop- 
erly performed  as  described,  a 
finished  piece  of  bridge-work  is  the  result. 

In  constructing  bridge-work  most  prefer,  after  the  porcelain 
fronts  are  backed  and  the  caps  forming  the  occluding  surfaces  of 
the  bicuspids  and  molars  are  properly  adjusted  on  the  model,  to 
invest  and  do  the  entire  soldering  at  once.  When  this  plan  is 
followed,  pieces  of  gold  wire  or  plate  should  be  laid  lengthwise 
in  the  slots  under  the  gold  caps  of  the  porcelain  fronts,  all  inter- 
stices packed  with  gold  foil,  and  the  parts  filled  in  and  all  the 
sections  of  the  bridge  joined  together  in  the  soldering.  By  this 
method  there  is  less  liability  of  fracturing  the  porcelain  fronts, 
but  warping  is  more  apt  to  occur,  the  soldering  is  more  difficult  to 
perform,  especially  for  a  novice,  and  the  finishing  of  the  bridge  is 
not  so  easily  done. 

How  to  Avoid  Warping. — In  large  pieces  of  work  warping 


CONSTRl  rilox  OF  BRIDGE-WORK.  197 

niay  be  avoided,  whichever  method  of  soldering  is  adopted,  by 
first  removing  the  "dummies"  from  the  model,  in  proper  position, 
partially  incased  in  plaster,  investing  and  soldering  those  of  each 
span  together.  The  spans  are  then  replaced  in  the  matrix  and 
soldered  to  the  abutment-. 

Construction  in  Sections — Another  method  much  prac- 
ticed and  which  gives  good  results  is  to  construct  the  bridge  in 
sections,  adjust  the  sections  in  the  mouth,  and  remove  them  in  an 
impression-tray,  using  only  sufficient  investing  material  to  cover 
the  points  of  the  teeth  and  crowns,  as  shown  in  Fig.  368.  The 
bridge  and  the  investing  material  are  then  removed  from  the  im- 
pression-tray, and  more  investing  material  is  added  to  complete 
the  investment.     The  sections  of  the  bridge  to  be  united  are  then 

Fig.  368. 


exposed  and  soldered  together.  To  permit  the  investing  material 
to  be  easily  removed  from  the  impression-tray,  it  is  well  to  melt 
a  film  of  wax  on  the  interior  surface,  then  cool  and  serrate  the 
surface  of  the  wax.  The  plaster  will  firmly  adhere  to  the  wax, 
but  will  loosen  when  the  tray  is  heated.  In  the  case  just  described, 
the  right  and  left  cuspids  and  molar  sections  could  be  made  first, 
adjusted  in  position,  the  incisors  then  formed  between  them,  and 
all  soldered  together;  or,  the  front  section,  consisting  of  the  cus- 
pids and  incisors,  could  be  first  made,  and  then  the  rear  exten- 
sions to  the  molars  added.  The  crowns  or  caps  that  constitute  the 
piers  should  never  be  temporarily  removed  from  the  model  for 
any  purpose  and  again  replaced  to  finish  the  construction,  as  not 
the  slightest  variation  in  their  position  is  allowable. 

Adjustment  and  Attachment. — The  bridge  when  finished  is 


198 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORE. 


adjusted  in  the  mouth,  every  point  carefully  examined,  and  any 
alterations  required  are  then  made.  Should  the  edges  of  the 
collars  of  any  of  the  crowns  catch,  so  as  to  prevent  their  being- 
placed  in  position,  a  small  quantity  of  articulating  paste  (a  thin 
paste  of  rouge  and  oil)  should  be  applied  inside  the  cap  or  caps 
interfering,  and  the  point  found  and  trimmed  off.  If  extensive 
warping  has  occurred  in  the  soldering,  the  bridge  must  be  sawed 
apart  in  one  or  two  places,  adjusted  in  the  mouth,  and  removed 
in  an  impression-tray  as  shown  in  Fig.  368,  then  invested  and 
united  with  solder  in  corrected  position  in  the  same  manner  as 
already  described  in  "Construction  in  Sections." 

"When  the  adjustment  of  the  bridge  is  accomplished,  it  can  at 
first  be  temporarily  inserted  for  a  day  or  two,  if  desired,  which 
permits  it  to  settle  accurately  in  position,  and  define  surely  any 
slight  points  in  the  occlusion  which  may  seem  to  require  alteration. 
Should  there  be  evidence,  after  temporary  use,  of  the  need  of 
changes,  the  removal  of  a  little  of  the  occluding  surface  of  the  cap 
at  the  required  point,  and  of  the  antagonizing  teeth,  will  generally 
be  sufficient  to  correct  it.  If  the  bridge  is  warmed  and  paraffin,  to 
which  a  little  aristol  has  been  added,  is  placed  in  the  caps  before  in- 
serting, the  secretions  will  be  better  excluded  and  a  septic  odor  pre- 
vented. Burnishing  the  collars  will  usually  secure  the  bridge;  if 
not,  it  can  be  cemented  with  a  little  gutta-percha  placed  in  each  cap, 
instead  of  the  paraffin.  For  its  permanent  attachment  the  pins  or 
posts  of  the  crowns  are  barbed,  and  the  teeth  and  roots. to  which 
crowns  have  been  fitted  are  then  treated  the  same  as  single  crowns, 
and  the  bridge  cemented  on  with  oxyphosphate  or  gutta-percha 
cement.  The  end  of  the  bar  is  anchored  in  the  slot  by  either  a 
gold  or  an  amalgam  fill- 
ing. (See  chapter  on  "Bar 
Bridges.")  Fig.  369  rep- 
resents the  bridge  in  posi- 
tion. 

The  Construction  of 
Small  Pieces  of  Bridge= 
Work  is  much  simplified 
by  the  following  method : 
Crowns  are  first  made  for 
the  teeth  or  roots  that  form 
the  abutments  and  tempo- 


Fig.  3G9. 


CONSTRUCTION  OF  BRIDGE-WORE. 


199 


rarily  placed  in  position.  The  teeth — "dummies" — which  form 
the  span,  having  been  ground  and  backed,  with  or  without  the 
aid  of  a  model,  are  adjusted  and  attached  with  wax  cement 
in  proper  position  between  the  crowns.  The  crowns  and  dummies 
are  then  removed  together,  in  an  impression-tray  filled  with  in- 
vesting material.  The  inside  of  the  tray  should  be  previously 
oiled  or  coated  with  a  film  of  wax  and  the  surface  serrated.     The 

Fig.  370. 


Fir;.  371. 


900  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

impression-tray  is  then  heated,  and  the  investment  with  the 
crowns  and  dummies  removed;  more  investing  material  is  then 
mixed,  and  the  exposed  parts  of  the  crowns  and  teeth  covered. 
The  investment,  when  set,  is  then  cut  away  sufficiently  to  expose 
the  parts  that  are  to  be  filled  in  and  united  together  in  the  sol- 
dering process.  Figs.  370  and  371  represent  cases  of  bridge- 
work  constructed  in  this  manner.  Part  or  parts  of  a  large  bridge 
being  constructed  in  sections  may  be  similarly  formed  and  then 
united. 

In  an  extension  bridge  of  two  teeth,  often  a  preferable  method  is 
to  properly  adjust  crown  and  dummy  tooth  cemented  with  wax  in 
the  mouth,  carefully  remove  them  in  position,  then  invest  and 
solder  together. 


CHAPTEK    II. 

Special  Processes  and  Appliances  in  BridgeAYork. 

shoulders  on  the  anterior  crowns  or  artificial  teeth— solid 
porcelain  dummies  with  gold  base— diatoric  tooth  dummies 
— solid  gold  dummies— a  bar  anchorage  slot  in  a  solid 
gold  crown— all-gold  hollow  dummies— connecting  bands 
or  bars  for  bridges — intervening  roots— shell  crown  or 
anchorage— seamless  shell  crown— cementation  of  shell 
crowns— special  forms  of  shell  pin  crowns— the  car- 
michael  crown — the  staple  crown. 

Shoulders  on  Anterior  Crowns  or  Artificial  Teeth  are  some- 
times desirable,  especially  on  the  superior  cuspids  at  the  point  of 
occlusion  with  the  lower  teeth.  A  shoulder  can  be  made  by  melt- 
ing gold  plate  into  the  form  of  a  small  ball  or  globule,  then  flat- 
tening it  out  and  soldering  it  against  the  backing. 

Another  method  in  the  case  of  a  crown  is,  in  the  formation  of 
the  collar,  to  extend  it  toward  the  occluding  teeth,  Fl(J  3_.,  Fm  3_3 
as  shown  in  Fig.  372,  and  then  protect  the  incisal 
or  occluding  porcelain  with  a  strip  of  metal  ap- 
plied, as  illustrated  in  the  case  of  a  "dummy" 
tooth  in  Fig.  373,  which  is  to  be  reinforced  and 
additionally  filled  in  with  solder  to  the  dotted 
line  A.  by  specially  investing  or  in  the  soldering 
of  the  bridge.  The  strip  of  gold  should  be  extended  a  little  be- 
yond both  sides  of  the  backing  or  over  the  incisal  edge  of  the 
porcelain  to  retain  it  in  position  in  the  investment. 

Solid  Porcelain  Dummies  with  Gold  Base. — In  some  cases  of 
bridge-work  on  the  lower  jaw,  protection  of  the  incisal  edges  and 
occluding  surfaces  of  dummies  with  gold  renders  them  noticeable 
to  an  extent  which  is  very  objectionable  to  many  patients.  This 
can  be  remedied  in  bicuspids  by  forming  the  occluding  surface 
and  the  exposed  portion  of  the  labial  face  of  porcelain  in  the 
following  manner:  Select  a  suitable  sized  ordinary  bicuspid  de- 
signed for  vulcanite,  and  level  out  the  headed  portion  of  the  pin- 

20, 


202 


CROWN-,  BRIDGE-,  AMD  PORCELAIN  WORK. 


by  squeezing  with  pliers.  Cut  a  strip  of  pure  gold  about  No.  34 
gage,  of  a  size  to  encircle  the  tooth,  and  give  an  excess  in  length 
and  width  of  about  one-eighth  of  an  inch.  Trim  the  strip  to 
the  shape  seen  at  Fig.  374,  and  punch  a  hole,  A,  in  one  of  the 
corners.  Slip  this  over  the  left-hand  pin  A,  Fig.  375,  wrap  the 
gold  tightly  around  the  porcelain,  and  bring  it  over,  as  shown 
by  the  dotted  line,  on  to  the  right-hand  pin  marked  B.  Mark 
the  location  of  the  pin  and  punch  a  hole,  put  the  pin  through 
the  hole,  and  bring  the  gold  down  on  the  porcelain.     Outline 


Fig.  374. 


Fig.  375. 


Fig.  376. 


on  the  gold  enough  to  expose  the  porcelain  as  shown  in  Fig.  376. 

Remove  the  gold  and  cut  out  the  portion  marked.     Replace  the 

gold  on  the  tooth,  pinch  in  around  the  base  of  the  porcelain, 
and  cut  off  the  excess  of  length,  also  the  excess  at  the 
overlap  on  a  diagonal  line  so  as  to  make  an  even  joint. 
Bend  the  pins,  invest,  and  flow  solder  over  pins  and 
seam.  When  completed  you  will  have  a  dummy  of 
the  form  exhibited  in  Fig.  376,  which  can  be  placed 

in  position  and  attached  with  solder.     Saddle-back  teeth  instead 

of  plain  teeth  for  vulcanite  work  may  be  used  in  this  method. 
Diatoric  Tooth  Dummies* — Dr.  R.  M.  Sanger  has  devised  a 

method  of  using  diatoric  bicuspids  and  molars  set  in  a  gold  base 

or  socket,  which  form  a  dummy  of  considerable  merit,  both  as  to 

appearance  and  practicability. 

To  explain  the  construction  of  a  diatoric  tooth  dummy  a  bicus- 
pid will  be  used  as  a  typical  case. 

Fig.  377  outlines  the  plan  of  the  structure  of  a  dia- 
toric porcelain  tooth. 

The  tooth  is  selected  to  fit  the  case  with  as  little  grind- 
ing as  possible.      (The  form  in  which  they  are  made 

permits  the  cervico-buccal  edge  to  rest  on  the  gum  with  little  or 

no  grinding.) 


Fig.  377. 


SPECIAL  PROCESSES  AXD  APPLIANCES  IN  BRIDGE-WORK.    203 

A  piece  of  pure  gold  plate  of  about  No.  32  gage  is  cut  of  a  size 
sufficient  to  cover  the  base  of  the  tooth  and  project  over  the  edge 
about  one-sixteenth  of  an  inch.     This  is  laid  on  the  Fl(,  .,-s 

base  of  the  tooth  and  pressed  and  burnished  to  fit 
as  nearly  as  possible.     A  metal  ring  (Fig.  378,  A),  »  V 

small   enough   to  fit  in   a  crown  swager,  is  filled       '   W; :..--' A 
with  modeling  compound  and  the  occluding  sur-        ■} 
face  of  the  diatoric  tooth  is  pressed  into  the  com-       ^|j: 
pound,  as  shown  in  Fig.  378,  B.     The  compound 
is  chilled,  the  partly  fitted  piece  of  gold  plate  is  placed  in  position 
on  the  tooth,  and  the  whole  is  placed  in  a  swager  (page  119)  and 
covered  with  corn  meal.     The  plunger  is  then  inserted  and  the 
gold  swaged  to  fit  the  base  of  the  tooth  accu- 
rately.    On  removal,  the  margins  of  the  geld   ] 
are  trimmed  to  extend  slightly  beyond  the  edge 
of  the  base,  as  shown  in  Figs.  379  and  380.    The 
gold  is  then  burnished  around  the  edge  close  to 
the  porcelain  and  well  down  into  the  hole  in  the 
center.      It  will  probably  be   perforated  when   being  burnished 
into  the  central  hole;  the  burnishing  should  be  continued,  how- 
ever, until  the  metal  closely  fits  the  edges,  and  then  the  depres- 
sion is  partly  filled  with  gold  foil.     Next  remove  the  gold  socket 
from  the  tooth  and  fill  up  the  remainder  of  the  central  depression 
with  20-carat  solder  until  it  is  flush.     This  gives  a  gold  socket  and 
pin  which  firmly  hold  the  diatoric  tooth  and  take  the  place  of 
an  ordinary  gold  backing. 

Fig.  379  shows  the  socket  and  Fig.  380  the  socket  in  position 
on  the  diatoric  tooth.  When  the  teeth  and  sockets  are  set  up  in 
position  on  the  model  in  the  construction  of  the  bridge,  the  sockets 
are  waxed  to  each  other  on  the  lingual  side  and  to  the  piers.  The 
whole  can  then  be  removed  from  the  model,  correctly  adjusted  in 
the  mouth,  and  the  teeth  occluded  to  correct  any  error  in  the  occlu- 
sion of  the  diatoric  teeth.  The  diatoric  teeth  are  then  removed 
from  the  sockets,  and  afterward  the  piers  and  sockets  from  the 
mouth  in  an  impression  of  investing  material.  With  the  addition 
of  more  investing  material  to  protect  and  cover  the  piers,  the 
work  is  put  in  form  for  soldering.  The  approximal  surfaces  of 
the  sockets  are  joined,  and  for  additional  strength  a  piece  of  No. 
26  gage  gold  plate  is  laid  across  the  lingual  aspect  from  pier  to 
pier,  and  the  whole  uniformly  overflowed  with  solder  to  the  dotted 
15 


204 


CROWX-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  381. 


line  A,  Fig.  380,  so  as  to  give  form  to  the  part.     When  the  con- 
struction of  the  bridge  is  to  be  conducted  on  the  model,   the 
diatoric  teeth  are  removed  from  the  sockets,  the  sockets  and  pier:? 
covered  with  investing  material,  the  lingual  side  of  the  work  ex 
posed,  and  the  parts  soldered. 

If  the  base  of  the  bridge  is  to  be  made  to  rest  firmly  on  the 
gum  with  a  saddle,  the  shape  and  size  of  the  saddle  are  marked 
on  the  plaster  model,  the  model  is  slightly  scraped  to  insure  a  tight 
fit,  and  thin  platinum  is  burnished  or  swaged  to  fit  the  model. 
This  saddle  should  not  extend  beyond  the  line  where  the  cervico 
labial  edge  of  the  tooth  will  rest,  but  on  the  lingual  side  it  should 
extend  sufficiently  far  to  be  retained  in  position  by  the  investing 
material.  After  removing  the  wax  cement,  the  triangular-shaped 
space  between  the  dummies  and  the  platinum  is  packed  with  foil 
and  solder,  and  with  the  blowpipe  flowed  to  a  homo 
geneous  mass  filling  the  entire  space  flush  to  the 
lingual  surface,  as  in  Fig.  381,  A.  To  prevent 
possible  injury  to  the  fine  edges  of  the  sockets, 
the  polishing  should  be  done  with  the  porcelain 
teeth  in  position,  but  to  avoid  soiling  the  joints  the 
teeth  should  not  be  permanently  cemented  in  the 
sockets  until  the  polishing  is  completed.  The  teeth  may  be  per 
manently  fastened  in  the  sockets  with  oxyphosphate,  sulfur,  oi 
gutta-percha  cement.  They  are  replaceable  in  case  of  fracture 
without  removing  the  bridge. 

Solid  Gold  Dummies. — In  a  close  occlusion,  when  the  patient 
prefers  strength  to  appearance,  the  bicuspids  and  molars  may  be 
made  of  solid  gold.     They  are  constructed  by  stamp 
ing  up  the  cap   (A,   Fig.   381  a)   representing  the 
grinding-surface  (see  page  107),  adjusting  and  ce- 
menting to  this  with  wax  a  piece  of  plate  cut  and 
shaped  to  form  the  front  and  sides  (B),  the  whole 
being  then  invested  and  filled  in  with  gold  solder 
and  scraps  of  gold  plate,  or,  if  pure  gold  and  plati- 
num have  been  used  in  the  sections  of  the  crown,  witli  18-  or 
20-carat  plate. 

Seamless  contour  crowns  can  be  used  for  the  purpose  as  follows: 
The  proper  crown  having  been  selected,  the  gold  is  trimmed  and 
the  crown  adjusted  in  position  on  the  model.  A  matrix  of  plastei 
is  then  placed  on  the  labial  side,  to  hold  it  in  position  and  permit 


Fig.  381a. 


SPECIAL  PROCESSES  AXD  APPLIAXCES  IN  BRIDGE-WORK. 


205 


exposure  of  the  palatal  portion.  The  crown  is  then  removed,  and 
cut  away  to  the  form  required  on  the  palatal  or  lingual  side.  It 
is  next  invested  and  filled  in  with  scraps  of  gold  plate  and 
solder. 

A  bar  bridge  can  be  made  with  these  seamless  crowns  by  pass- 
ing a  platinum  wire  through  the  crowns  before  filling  in  (Fig. 
382). 

A  Bar=Anchorage  Slot  in  a  Solid  Gold  Crown,  to  support  the 
end  of  a  bar  as  shown  in  Fig.  383,  is  constructed  as  follows :  The 
natural  crown  is  ground  down,  and  the  neck  shaped,  banded, 
capped,  and  pivoted  as  in  Fig.  384.  The  gold  or  platinum  form- 
ing the  top  of  the  cap  on  the  root  is  made  perfectly  flat  and  left 


Fig.  3S3. 


Fig.  384. 


projecting  a  little  at  the  sides.-    A  contoured  crown 
of  pure  gold,  or  gold  lined  with  platinum  as  a  pre- 
caution  against   melting,   is   shortened  sufficiently       \  /   \  i  i 
to  represent  the  absent  coronal  section  of  the  tooth.  v" 

In  the  side  of  the  gold  crown  a  slot  is  cut  large  enough  to  form 
the  anchorage  cavity  the  bar  is  to  rest  in.  A  shell  of  thin  plati- 
num of  the  size  and  shape  of  the  anchorage  cavity  is  then  inserted 


Fig.  385. 


in  the  slot  and  cemented  with  wax  on  the  inside  of  the  crown. 
The  crown  is  then  invested  and  filled  in  with  scrap  plate  and  18- 
carat  gold  solder,  which  should  be  cut  into  small  pieces,  and  be 


206  CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORE. 

placed  successively  in  the  crown  and  melted  by  maintaining  a 
uniform  heat  with  the  large  flame  of  a  blowpipe.  The  base  of  the 
crown  is  next  ground  level  and  accurately  fitted  to  the  cap  so 
that  the  occluding  surface  shall  properly  articulate  with  the 
antagonizing  teeth.  It  is  then  clamped  to  the  cap  in  position,  the 
posts  having  first  been  protected  with  investing  material  (Fig. 
385),  and  soldered,  making  a  perfect  joint.  This  is  an  easy 
method  of  constructing  an  otherwise  difficult  form  of  crown. 

Fig.  386  illustrates  from  the  palatal  side  a  bridge  of  two  solid 
gold  bicuspid  dummies  supported  by  a  bar-anchorage  in  a  solid 
gold  crown  on  the  roots  of  a  molar,  and  a  shell  crown  on  a  cuspid. 

AIUGoId  Hollow  Dummies  are  recommended  in  a  large  pro- 
portion of  cases  in  preference  to  solid  ones,  especially  for  the 
upper  jaw.      They  are  formed  as  follows:     Take  a  gold  seam- 

Fig.  386. 


less  contour  crown  of  suitable  size,  with  a  thick  grinding- 
surface,  or  one  which  has  been  reinforced  with  solder  or  gold 
plate  and  from  which  the  flux  is  removed.  Cut  away  the  gold 
forming  the  palatal  section  of  the  collar  to  the  form  termed  self- 
cleansing;  or  shape  the  neck  of  the  crown  to  the  exact  contour 
of  the  portion  of  the  gum  the  dummy  is  to  rest  on.  Melt  a  small 
quantity  of  solder  with  flux  to  a  ball  form.  Fit  a  piece  of  plati- 
num plate,  about  Xo.  32  gage,  over  the  open  end,  and  place  the 
ball  of  solder  on  the  platinum  within  the  gold  cap.  (See  Fig. 
387.)  Hold  cap  and  platinum  in  a  Bunsen  flame,  and  heat  slowly 
until  the  solder  melts  and  appears  under  the  edge  of  the  cap; 
then  instantly  remove  from  the  flame,  trim  the  platinum,  and 
stone  the  edges.  This  gives  a  hermetically  inclosed  dummy  tooth 
of  gold,  from  the  interior  of  which  the  air  has  been  exhausted 
by  the  heat.  The  dummy  can  then  be  placed  in  its  position  on  the 
bridii'e   and   soldered  in  the  usual  manner.      If  the  base  of  the 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-VORK. 


207 


dummy  is  to  rest  on  the  gum,  a  little  of  the  plaster  should  be 
scraped  away,  sufficient  to  make  some  allowance  for  the  thickness 
of  the  platinum  forming  the  base,  and  cause  pressure  and  insure 
closeness  of  fit.  Fig.  388  gives  the  palatal  aspect  of  a  bridge,  the 
dummies  of  which  were  constructed  in  the  manner  described. 
The  bicuspid  dummy  is  given  a  self-cleansing  form,  and  the 
molar  is  shaped  to  rest  on  the  gum. 

Fig.  387.  Fig.  388. 


Fig.  389. 


The  use  of  hollow  gold  dummies  is  a  saving  of  time  and  ex- 
pense to  the  operator;  being  of  light  weight,  in  many  cases  they 
are  preferable  to  solid  ones.  For  the  lower  jaw  they  can  be 
shaped  advantageously  to  the  form  shown  in  Fig.  389, 
thus  overcoming  the  annoyance  of  the  so-termed  self- 
cleansing  spaces.  The  collar  section  of  the  crown  is 
slit  on  the  sides  A,  shaped  and  bent  inward  toward  the 
neck  at  the  buccal  as  well  as  lingual  sides,  and  the 
neck  trimmed  at  the  edges-  to  fit  the  shape  of  the 
alveolar  ridge  and  the  slits  soldered.  The  opening  is 
<"hen  closed  with  platinum,  as  shown  in  Fig.  387. 


Connecting  Bands  or  Bars  for  Bridges,  which  obviate  the  re- 
moval of  crowns  of  intervening  natural  teeth  between  the  sections 


208 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


of  a  projected  bridge,  are  formed  by  passing  a  heavy  band  of  round 
or  oval-shaped  gold  or  iridio-platinum  wire  around  the  intervening 
teeth,  close  to  but  not  touching  them,  and  pressing  slightly  into 


Fig.  391. 


Fig.  392. 


the  gum  so  as  not  to  present  too  pronounced  an  interference  to  the 
tongue.  This  is  accomplished  by  slightly  indenting  the  bar  in 
the  surface  of  the  model  before  soldering.  (See  Figs.  390,  391, 
and  392.) 

Fig.  393. 


Intervening    Roots    between   the    abutments    of   a   projected 
bridge  should  not  be  extracted,  but  whenever  practicable  they 


SPECIAL  PROCESSES  AND  APPLIANCES  IN  BRIDGE-WORK.    209 


should  be  treated,  filled,  and  trimmed  level  with  the  gum,  as  they 
can  usually  be  made  to  afford  some  support  for  the  bridge,  which 
may  rest  upon  them.  Fig?.  393  and  394  represent  a  case  in  which 
the  root  of  the  cuspid  on  the  right  side  has  been  so  treated  and 
utilized. 

Shell  Crown — A  shell  crown  or  anchorage  for  a  cuspid  to 
support  bridge-work,  if  the  conditions  will  permit,  is  preferably 
used  instead  of  a  gold  collar  crown  with  porcelain  front,  where 
the  insertion  of  such  a  form  of  crown  involves  the  excision  of  a 
natural  crown  with  a  living  pulp.  A  convenient  method  of  con- 
struction is  the  following :     Shape  the  natural  crown  parallel  on 

Fig.  394. 


Fig.  396. 


the  sides,  and,  if  necessary,  remove  a  little  of  the  bulge  at  the 
labio-cervical  section.  Construct  and  adapt  to  the  cervix,  and 
slightly  under  the  gum-margin  of 
the  natural  crown,  a  gold  collar  wide 
enough  to  extend  a  little  beyond  the 
incisal  edge.  Remove  a  portion  of 
the  gold  from  the  incisal  labial  sec- 
tion, and  slit  the  palatal  surface  on 
both  sides  of  its  center,  as  repre- 
sented in  Pigs.  395  and  396.  The 
part  at  A  is  bent  back,  and  the  parts  at  B  B  beveled,  bent  in  on 
the  crown,  and  burnished  close  to  its  surface.  The  piece  A  is 
next  brought  down  in  position,  and  adapted  to  the  crown  and  over 
the  parts  B  B. 


210 


CROWN ■-,  BRIDGE-,  AND  PORCELAIN '-WORK. 


The  collar  has  now  assumed  the  form  of  a  gold  crown  having 
an  open  face  and  seams.  The  seams  are  next  united  by  flowing 
solder  into  each  of  them,  a  little  at  a  time,  by  holding  the  crown 
with  tweezers  in  a  Bunsen  gas  flame.  The  seams  will  hold  and 
retain  solder  sufficient  to  join  and  fill  them  without  its  flowing 
over  the  adjacent  parts,  unless  there  is  an  excess  of  heat  or  solder. 
When  the  soldering  is  completed,  the  crown  is  adjusted,  a  line 
showing  the  exact  portion  of  the  labial  aspect  to  be  exposed 
marked  on  the  gold,  the  crown  removed,  its  edges  trimmed  to  the 
mark,  and  the  soldered  parts  smoothed  with  corundum-wheels  and 
points  on  the  engine. 

Another  method  for  the  construction  of  a  shell  crown  prefer- 
ably practiced  by  some  is :  Fit  a  gold  collar  around  the  natural 
crown,  and  remove  the  gold  at  the  labial  aspect,  as  shown  at  A, 
Fie;.  397.     In  the  vacancy  between  the  collar  and  tooth  at  the 


Fig.  397. 


palatal  side,  fit  and  burnish  a  piece  of  pure  gold,  or,  in  the  case 
of  a  very  close  bite,  thin  platinum  plate,  which  will  cover  the  ex- 
posed surface  of  the  tooth  at  that  part,  and  fill  in  the  space  be- 
tween the  collar  and  piece  of  plate  with  wax  cement.  D,  Fig.  397, 
shows  the  form  generally  of  the  piece  of  plate  before  it  is  fitted 
in  the  collar.  Remove  the  collar,  invest,  and  flow  solder  into  the 
space  between  the  piece  of  plate  and  collar,  and  remove  the  sur- 
plus gold  of  the  collar  extending  above  the  crown;  B  and  C  show 
the  finished  shell  crown. 

A  Seamless  Shell  Crown  is  formed  as  follows:  From  an  im- 
pression of  a  natural  crown  taken  in  plaster,  or  moldine,  a  die  of 
fusible  metal  is  formed,  and  from  it  a  counter-die  in  lead  is  made. 
(See  chapter  on  "Gold  Seamless  Cap-Crown.")  On  the  die  a 
crown  is  shaped,  burnished,  and  then  stamped  from  a  seamless  cap 


SPECIAL   PROCESSES  AND  APPLIANCES  IN  RRIDGE-V'ORK. 


211 


of  gold  (Fig.  398).  This  crown  is  then  fitted  on  the  natural 
tooth,  the  labial  aspect  of  which  is  exposed  by  the  removal  of  the 
section  of  gold  covering  it  in  either  of  the  forms  shown  in  Fig. 
399.  A  shell  crown  for  a  cuspid  may  be  made  for  some  cases 
from  a  gold  collar  by  shaping  the  collar  on  a  die  of  the  tooth,  the 
same  as  a  gold  cap.  The  shell  formed  in  whatever  manner  is  then 
filled  with  investing  material,  and  strengthened  by  flowing  20- 
carat  solder  over  the  surface. 


Fig.  398. 


Fig.  399. 


For  cuspids  this  process  has  decided  advantages  in  the  easy 
formation  of  a  perfect-fitting  crown  or  shell  for  bridge-work. 

Fig.  400  shows  the  forms  usually  given  shell  crowns  for  bi- 
cuspids.   "When  the  gold  is  removed  at  the  labio-cervical  part,  the 


Fig.  400. 


Fig.  401. 


crown  should  be  additionally  secured  by  a  pin  introduced  and 
soldered  at  the  point  A. 

Fig.  401  illustrates  a  bridge  in  which  the  lower  incisors  are 
supported  by  shell  crowns  on  the  cuspids. 

In  cases  where  this  form  of  crown  is  expected  to  sustain  a 
great  strain,  the  gold  at  the  cervico-labial  section  should  be  re- 
inforced by  the  addition  of  a  strip  soldered  across  it  and  extend- 


212 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


ing  around  on  the  sides,  as  shown  in  Fig.  402.     The  edge  of  the 
strip  should  be  beveled  off  even  with  the  surface  of  the  rest  of  the- 


gold. 


Fig.  403  represents  the  restoration  of  the  inferior  bicuspids  and 
Fig.  402.  Fig.  403. 


molar  on  the  right  side,  by  a  bridge  with  a  shell  crown  on  the 
cuspid  and  an  all-gold  crown  on  the  second  molar  as  abutments. 
The  Cementation  of  Shell  Crowns. — To  secure  a  better  adhe- 
sion of  the  cement  in  the  cementation  of  such  caps,  the  surface- 
of  the  enamel  should  be  cleaned  with  pulverized  pumice  wet  with 
aromatic  sulfuric  acid.  The  tooth  is  then  washed  and  dried  per- 
fectly. The  cement  should  be  thoroughly  mixed  to  the  consist- 
ence of  a  thick  cream,  the  inside  of  the  band  covered  with  it,  and 
then  the  surface  of  the  tooth  and  the  bridge  brought  to  position. 
AVhen  the  strip  of  gold  which  traverses  the  cervico-labial  section 


Fig.  404. 


Fig.  405. 


is  made  narrow,  the  washing  out,  in  time,  of  the  cement  at  that 
part,  especially  when  oxyphosphate  is  used,  is  one  of  the  diffi- 
culties connected  with  the  use  of  this  form  of  crown. 

Fig.  404  shows  a  pin  shell  crown  that  covers  all  but  the  labial 
face  of  the  tooth,  which  can  be  made  to  support  a  porcelain  front 
representing  a  cuspid  or  bicuspid.  By  forming  two  grooves,  re- 
spectively in  the  mesial  and  distal  sides  of  the  natural  tooth,  for 


SPECIAL  PROCESSES  i.YZ)  APPLIANCES  IN  BRIDGE-WORK. 


213 


the  reception  of  platinum  pins  passing  through  the  grinding- 
surface  of  the  cap  and  fastened  with  a  little  solder  on  the  outside, 
much  more  security  of  attachment  is  obtained  with  a  partial  cap, 
and  without  the  least  exposure  of  gold.  (See  Fig.  405.)  In  a 
favorable  case  a  central  or  cuspid  cap  may  be  formed  on  this  plan 
to  support  a  lateral.  A  third  pin  placed  at  the  palatal  side  toward 
the  cervix  will  tend  to  additionally  secure  the  cap. 

In  most  cases  where  shell  crowns  are  used  on  the  upper  jaw,  the 
gold  forming  the  distal  side  of  the  cap  can  be  brought  around 
slightly  on  the  labial  surface  of  the  tooth  without  being  observable 
when  viewed  from  the  front;  but  it  must  be  cut  short  at  the  mesial 
side  and  not  be  allowed  to  extend  beyond  the  line  of  the  porcelain 
front  placed  alongside  of  it.  On  the  lower  jaw  the  band  of  gold 
which   extends   across  the   labial    aspect   need   only   be   removed 


Fig.  40G. 


enough  to  avoid  exposure  in  speaking.  On  the  lower  jaw  much 
more  gold  can  be  left  at  the  cervico-labial  section  than  on  the 
upper,  as  only  enough  need  be  removed  at  the  incisal  edge  to 
avoid  exposure  of  the  metal. 

The  Carmichael  Crown  consists  of  a  gold  cap  which  covers  a 
little  more  than  half  of  the  natural  crown  standing  toward  the 
palatal  or  lingual  side,  and  is  retained  by  a  groove  which  runs 
across  the  incisal  or  occlusal  surface  and  along  the  sides.  The 
tooth  is  prepared  as  follows :  Trim  parallel  from  the  palatal  to 
the  center  of  the  mesial  and  distal  sides  the  surfaces  of  each  tooth 
to  be  capped.  Sufficient  of  the  tooth  should  be  cut  away  to  give  a 
form  to  the  section  to  be  covered  which  will  accommodate  the 
thickness  of  the  metal  and  permit  the  caps  to  be  drawn  on  and  off 
without  spreading  at  the  margins.     Enough  of  the  occlusal  sur- 


214 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


faces  is  also  to  be  removed  to  allow  for  the  thickness  of  the 
gold  which  will  cover  that  part.  With  a  thin  disk  cut  a  groove 
directly  across  the  incisal  or  occlusal  surface.  In  the  case  of  an 
incisor  or  cuspid  the  cut  is  made  near  the  front  plate  of  enamel, 
but  not  so  close  as  to  weaken  it;  in  a  bicuspid,  across  between 
the  cusps  a  little  toward  the  outer  cusp;  in  molars,  across  the 
center.  With  a  short  enamel  fissure-bur,  cut  two  side  grooves  on 
the  lateral  surfaces,  connecting  with  the  groove  across  the  crown, 
and  extending  to  the  line  of  the  gum-margin.     (See  Fig.  406.) 

Fig.  407. 


The  grooves  form  the  mechanical  retention.  They  should  be 
moderately  deep,  in  shape  the  full  half  of  a  circle,  be  uniform  in 
size,  and  parallel  to  each  other.  Fig.  407  represents  Dr.  Car- 
michael's  device  for  gaging  the  lines  of  the  grooves  and  sides  of 
the  teeth  that  are  capped. 

To  form  the  cap,  take  an  impression  of  the-  prepared  tooth 
and  make  a  fusible-metal  die.  On  this  die  shape  a  cap  of  pure 
gold,  No.  37  gage,  by  adapting,  folding  the  meeting  edges,  and 
burnishing  down  the  metal.    For  bicuspids  and  molars  lay  the  strip 


SPECIAL  PROCESSES    IND  APPLIANCES  IX  BRIDGE-WORK.    215 


across  the  occlusal  surface,  bend  the  ends  down  on  the  mesial  and 
distal  sides,  and  then  crimp  the  gold  together  closely  at  the  palatal 
side.  Xext  give  the  flaps  two  flat  folds  to  hold  them  together  and 
leave  the  fold  projecting  from  the  tooth.  In  soldering,  this  pro- 
jecting fold  is  utilized  to  hold  the  cap.  In  incisors  and  cuspids 
bring  the  end  of  the  strip  over  the  incisal  edge  and  crimp  the  gold 
at  the  mesial  and  distal  corners  of  the  incisal  edge.  Bind  the  cap 
upon  the  die,  and  also  when  fitted  on  the  natural  tooth,  with  floss 
silk  to  prevent  it  from  springing  away  while  burnishing.  Burnish 
the  gold  in  the  grooves  first  on  the  die,  then  on  the  tooth,  and 
flow  in  solder  by  degrees.  After  each  soldering  fit  the  cap  on 
the  tooth  in  the  mouth  to  assure  accuracy.  Should  any  breaks 
occur  in  burnishing  the  gold  in  the  grooves,  pack  in  gold  foil. 
When  the  grooves  are  soldered,  stiffen  the  whole  surface  of  the 
cap  with  small,  thin  pieces  of  clasp-gold,  Xo.  fig.  to8. 

34  gage,  laid  on  in  succession  a  few  at  ;i 
time,  and  attached  with  solder.  The  solder- 
ing is  best  done  on  a  charcoal  block.  A  little 
dampened  marble-dust  or  investing  material 
may  be  placed  inside  the  cap  to  prevent  in- 
vasion of  solder.  Trim  and  finish  the  sur- 
face of  the  cap.  Fig.  406  shows  teeth  pre- 
pared ready  to  receive  the  caps.  Fig.  408, 
a  cap  off  and  in  position.  Figs.  409  and  410, 
a  case  of  bridge-work  constructed  with  these 
caps. 

The  Staple  Crown.1 — The  staple  crown  is  similar  in  principle 
to  the  Carmichael,  differing  only  in  the  use  of  a  platinum  wire  to 
fit  the  groove  in  the  tooth  for  the  retention  of  the  crown  instead 
of  a  projection  of  the  plate,  as  shown  in  Fig.  414.  The  prepara- 
tion of  the  natural  crown  is  much  the  same  for  either.  For  the 
staple  crown  the  groove  requires  to  be  made  very  iiniform  in 
size,  so  that  the  wire  shall  fit  it  evenly.  The  gold  cap  is  adjusted 
over  the  wire  and  burnished  on  each  side  of  it  so  as  to  set  the  wire 
in  a  slight  depression  of  the  plate  and  permit  it  to  be  removed  in 
position  with  the  cap.  The  wire  is  next  attached  to  the  cap  with 
minute  pieces  of  solder,  which  are  placed  along  the  wire  on  the 
inside  of  the  cap,  one  piece  at  a  time.    The  soldering  can  be  done 


A.  Groove  in  tootb. 

B.  Cm  p. 

a,  »  m  p  in  position. 


Dr.  F.  L.  Marshall,  Boston. 


216 


CltOlYN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


in  a  Bunsen  flame.  Only  barely  enough  solder  should  be  used  to 
attach  the  wire  so  as  to  avoid  obstruction  to  the  adjustment  of  the 
crown. 

Another  method  for  the  construction  of  this  style  of  crown  is 
to  attach  the  staple  to  the  piece  of  plate  before  adapting  the  plate 
to  the  tooth,  as  follows :     Cut  the  ends  of  the  staple  of  the  proper 

Fig.  409. 


Fig.  410. 


length  to  fit  the  grooves,  having  the  cross-bar  flush  with  the 
palatal  portion  of  the  tooth.  (See  Fig.  411.)  Take  a  thin  piece 
of  pure  gold  from  jSTo.  30  to  35  gage,  and  large  enough  to  fully 
cover  the  back  of  the  tooth.  Grasp  the  staple  in  a  pair  of  pliers, 
hold  in  contact  with  the  piece  of  pure  gold  at  about  the  angle 
illustrated  in  Fig.  412,  and  solder  with  22-carat  solder  at  the 
point  of  contact.  Bend  the  gold  loosely  around  the  sides  of  the 
staple  and  trim  the  cervical  portion.  Place  the  staple  in  the 
groove  and  at  first  adapt  it  either  on  the  mesial  or  distal  side  of  the 
tooth,  and  burnish  the  gold  against  the  surface  and  the  staple. 
(See  Fig.  413.)  Remove  and  solder.  Replace  the  crown,  burnish 
the  gold  closely  to  the  palatal  and  other  side  of  tooth  and  staple, 
and  remove  and  solder.  Again  replace  and  burnish  all  around  the 
free  edges  and  trim  off  the  surplus.  Remove,  invest,  and  stiffen  up 
the  whole  surface  of  the  crown  with  small  pieces  of  plate  and 
solder  as  before  described  in  the  Carmichael  crown.     Fig.  414 


SPECIAL  PROCESSES  AXD  APPLIANCES  IN  BRIDGE-WORK. 


217 


represents  the  finished  crown.  In  the  construction  of  bicuspid 
and  molar  crowns,  the  collar  section  is  formed  of  a  strip  of  gold 
plate  as  follows :  Cut  a  band  of  gold  the  same  as  for  a  full  crown, 
but  shorter.  Solder  one  side  of  the  staple  at  about  one-sixteenth 
of  an  inch  from  one  end  of  this  band.  Place  the  staple  on  the 
tooth,  draw  the  gold  around  the  tooth  to  the  opposite  side,  burnish 
tightly  to  the  neck  and  against  the  staple,  and  remove  and  solder. 
Strike  up  a  piece  of  plate  to  the  form  of  the  cusps,  fit  to  the  top 
of  the  band,  and  snider  the  cap  at  its  point  of  contact  with  the 


Fig.  411. 


Fig.  412. 


Fig.  413. 


\SY 


Fig.  414. 


Fig.  415. 


Fig.  41G. 


i 


staple.  Adjust  on  tooth,  and  have  the  patient  bite  firmly  to  adjust 
to  occlusion.  Burnish  the  edge  of  the  cap  to  the  outer  cusp  of  the 
tooth  and  also  to  the  band.  Eemove,  and  solder  the  edges  of  the 
cap  to  the  band. 

To  stiffen  up. the  crown,  boil  in  acid,  fill  the  inside  with  invest- 
ing material  and  flow  solder  over  the  surface,  or  use  clasp-plate 
and  solder  as  directed  for  the  Carmichael  crown.  Fig.  415  shows 
the  prepared  tooth,  and  Fig.  416  the  finished  bicuspid  crown. 

The  method  of  forming  the  Carmichael  crown  of  one  piece  of 
metal  may  be  applied  in  the  construction  of  the  staple  crown. 


CHAP  TEE    III. 

Extension  Bridges, 
principles    governing— construction— spur     support— a     spur 

ANCHOR. 

Tins  term  "extension"  is  applied  to  bridges  chiefly  supported 
by  one  abutment.  In  relation  to  the  anterior  teeth,  it  means 
attaching  a  dummy  to  an  artificial  crown,  to  replace  an  adjoin- 
ing absent  tooth.  A  bridge  of  this  style  replacing  two  or  three 
of  the  posterior  teeth  is  formed  by  using  two  of  the  teeth  anterior 
to  it  as  one  abutment,  with  a  saddle  for  the  other.  A  saddle 
is  an  oval-shaped  piece  of  gold,  or  platinum  plate,  of  the  form  of 
the  gum  and  a  little  larger  than  the  base  of  the  tooth,  placed  under 
the  posterior  tooth  of  the  bridge. 

In  extension  bridge-work,  the  portion  which  constitutes  the 
bridge  exerts  on  the  abutments,  in  resisting  the  force  of  occlusion, 
an  action  like  that  of  a  lever.  The  ratio  of  the  force  exerted  is 
proportioned  to  the  length  of  the  bridge  or  lever  from  the  abut- 
ment or  fulcrum.  This  principle  must  receive  consideration  in 
the  employment  of  this  form  of  bridge.  A  flange  or  spur  sup- 
port, if  attainable,  should,  as  a  rule,  be  applied.  More  than  one 
tooth  should  not  be  extended  from  an  abutment  without  ample 
alveolar  support  besides.  When  two  approximal  crowns  support 
an  extension  bridge  tooth  or  dummy,  the  force  is  counterbalanced 
by  the  resistance  of  the  farthest  anchorage  crown  from  the  bridge, 
the  pressure  on  which  is  in  a  direct  line  from  the  socket,  the  ap- 
proximal crown  acting  as  a  fulcrum,  the  force  on  which  is  upward 
in  the  line  of  the  root.  The  occluding  surfaces  of  the  bridge 
tooth  should  not  be  extended  from  an  abutment  without  ample 
to  offer  less  occluding  surface  to  the  antagonizing  teeth,  which 
should  barely  touch. 

Construction.- — Figs.  417  and  418  represent  an  extension 
bridge.  A  crown  on  the  cuspid,  an  all-gold  crown  on  the  first 
bicuspid,  and  a  saddle,  are  the  abutments.  In  constructing  this 
218 


EXTENSION  BRIDGES. 


219 


bridge,  the  crowns  to  form  the  abutments  were  first  constructed 
and  united  with  solder.  The  crowns  were  then  adjusted  in 
position,  and  an  impression  and  articulation  taken  in  plaster, 
in  which  the  crowns  were  removed.  From  this  impression  a 
model  was  made  of.  plaster  and  marble-dust,  and  an  articula- 
tion in  plain  plaster.  With  the  crowns  in  position  on  the 
model  as  in  the  mouth,  the  bridge  was  then  constructed  by  the 
methods  described  on  page  191.  The  part  of  the  model  on  which 
the  saddle  rested  was  marked,  and  enough  of  the  surface  of  the 
plaster  removed  to  cause  the  saddle  to  press  tightly  against  the  soft 


Fig.  417. 


Fig.  419. 


Fig.  418. 


Fig.  420. 


tissue  when  the  bridge  should  be  completed  and  inserted  in  the 
mouth.  This  can  also  be  more  accurately  accomplished  by  mark- 
ing the  space  the  saddle  is  to  occupy  on  the  surface  of  the  impres- 
sion, and  fitting  thereto  a  disk  of  thin  sheet  lead  of  from  !STo.  22 
to  30  gage  as  the  hardness  of  the  membranes  suggests.  The  space 
occupied  by  the  lead  will  cause  a  proportionate  depression  on  the 
model  when  made.  As  the  edges  of  the  saddle  should  press  more 
forcibly  against  the  tissues  than  the  central  portion,  it  is  well  to 
slightly  scrape  the  plaster  at  the  margins.  A  bridge  of  this  char- 
acter should  be  temporarily  inserted  and  worn  for  two  or  three 
days  to  allow  the  saddle  to  depress  the  tissues  and  permit  the 
bridge  to  settle  into  its  proper  position  before  permanently  ce- 
16 


220 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


menting  it.  In  the  cementation  of  the  bridge  care  should  be 
taken  that  no  particles  of  oxyphosphate  remain  under  the  saddle. 

All-gold  crowns  which  are  to  sustain  the  strain  of  an  extension 
bridge  should  be  stiffened  with  solder  so  as  to  possess  great  rigidity. 
If  this  precaution  is  not  taken,  the  constant  springing  motion  of 
the  extension  bridge  will,  in  some  cases,  gradually  bend  the  gold 
of  the  side  of  the  gold  crown  away  from  the  surface  of  the  natural 
tooth,  and  cause  leakage  by  disintegration  of  the  cement. 

A  shell  crown  on  a  cuspid  can  be  used  as  an  abutment  in  this 
style  of  bridge  to  support  a  lateral  in  many  cases,  instead  of  excis- 
ing the  natural  crown  and  mounting  an  artificial  crown  on  the 
root  for  the  purpose  (Figs.  419  and  420). 

Figs.   421   and   422,   423   and  424,   represent   small  extension 


Fig.  421. 


Fig.  423. 


Fig.  422. 


Fig.  424. 


bridges  of  frequent  construction,  the  former  for  the  anterior  por- 
tion of  the  mouth,  the  latter  to  replace  posterior  teeth. 

Dr.  T.  Fillebrown's  method  of  constructing  a  bicuspid  or  molar 
all-gold  crown  when  the  sides  of  the  natural  tooth  have  not,  for 
some  reason,  been  reduced  in  dimensions  to  those  of  the  cervix,  is 
to  first  form  and  fit  a  full-sized  collar  of  thin  pure  gold,  then  adapt 
and  solder  over  it  a  second  and  narrower  collar  of  thin  22-carat 
gold  plate,  extending  only  from  the  occluding  surface  about  half 
the  distance  to  the  gum-margin.  The  cap  for  the  occluding  surface 
is  then  added  in  the  usual  manner.     When  the  finished  crown  is 


EXTENSIOX  .BRIDGE*. 


221 


cemented  in  position,  and  while  the  cement  is  yet  quite  soft,  a 
burnisher  is  passed  around  the  neck  of  the  crown,  and  the  pure 
gold  forming  that  part,  as  represented  by  A,  Fig.  425,  is  brought 
close  against  the  neck  of  the  natural  tooth.  This  method  of  form- 
ing a  gold  crown  may  be  advantageously  practiced  in  some  of  these 
cases  of  bridge-work. 

Figs.  426,  427,  and  428  represent  an  extension  bridge.     The 
anterior  abutment  consists  of  the  six  front  teeth,  which  were  all 


Fig.  425. 


Fin.  426. 


JC 


Fig.  427. 


Fig.  428. 


crowned  and  joined  together,  the  pulps  being  preserved  in  the 
incisors.  A  saddle  on  each  side  forms  the  posterior  abutments. 
In  cases  similar  to  this,  when  the  dummies  are  extended  to  such 
an  extreme  distance  posterior  to  the  abutments,  if  antagonizing 
molars  are  present,  a  mere  saddle  is  insufficient  to  equalize  the 
strain,  especially  as  absorption  goes  on  to  some  extent  under  the 
saddle.     An  extension  of  not  over  two  teeth,  consisting  of  one 


222 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


bicuspid  and  a  molar  on  each  side,  resting  on  a  plate  or  saddle 
extending  from  the  cuspids  back  beyond  the  bridge  teeth  or  dum- 
mies, is  suggested  instead. 

A  Spur  Support  consists  of  a  flange  formed  at  the  end  of  an 
extension  bridge,  affording  support  by  resting  against  the  palatal 
wall  of  an  incisor  or  a  cuspid,  or  in  the  sulcus  between  the  cusps 
of  a  bicuspid  or  molar,  as  shown  in  Fig.  429.     Fig.  430  illustrates 


Fig.  429. 


Fig.  431. 


Fig.  432. 


a  case  with  a  spur  resting  against  a  cuspid.  In  the  case  repre- 
sented in  Figs.  431  and  432  the  spur  rests  in  an  indentation  in  an 
amalgam  filling  in  the  molar.  This  form  is  termed  a  cantilever 
bridge. 

A  spur  support  is  best  formed  as  follows:  "When  the  dummies 
are  mounted  on  the  model  ready  for  investment,  adapt  on  the 
model  of  the  tooth  where  the  spur  is  to  rest  a  piece  of  very  thin 
platinum.  Place  on  the  surface  of  the  platinum,  when  adjusted, 
a  still  narrower  piece  of  gold  plate.  Wax  them  in  position  and 
invest.  The  ends  of  the  platinum  and  plate  should  be  left  extend- 
ing farther  across  the  tooth  than  will  lie  required  for  the  spur,  to 
furnish  a  means  of  retaining  the  metal  in  position  in  the  invest- 


EXTENSION  BR  IDC  I.  S. 


223 


merit  during  soldering.    The  wax  should  cover  only  the  portion  of 
the  spur  to  be  soldered. 

A  Spur  Anchor. — A  spur  anchor  consists  in  the  addition  to  a 
spur  of  a  pin  which  anchors  but  is  not  cemented  in  a  filling  placed 
in  the  side  of  a  supporting 
tooth.  An  amalgam  or  gold 
filling  is  inserted  in  a  deep 
cavity  formed  in  the  side  of  a 
tooth,  as  illustrated  in  Fig. 
433,  which  represents  a  typi- 
cal case.  A  hole  is  drilled  in 
the  center  of  the  filling  about 
one-sixteenth  of  an  inch  in 
depth,  large  enough  to  loosely 
receive  a  platinum  or  gold 
pin  of  about  ISTo.  16  gage.  A 
disk  of  platinum,  large  enough  to  cover  the  filling,  is  adapted  to 
its  surface  and  perforated  over  the  orifice  of  the  hole.  The  end 
of  the  pin  is  cemented  in  position  with  wax,  invested,  and  first 
connected  to  the  disk  with  a  small  quantity  of  solder.  Disk  and 
pin  are  next  placed  in  position  in  the  mouth  and  the  disk  bur- 
nished to  the  surface  of  the  filling.  The  disk  is  removed  and 
trimmed  so  that  it  shall  be  a  line  smaller  than  the  surface  of  the 
filling  and  so  that  its  edges  shall  not  rest  on  or  touch  the  enamel 
of  the  tooth  at  any  point. 

The  bridge  is  then  constructed  in  the  usual  manner.  The  crown 
for  the  posterior  tooth  and  the  disk  are  placed  in  position,  an  im- 
pression taken,  and  a  model  made  in  which  the  crown  and  disk 
appear  in  position.  In  the  further  construction  the  disk  is  rein- 
forced with  solder  and  becomes  part  of  the  bridge.1 

Another  method  is  to  form  a  plain  spur  in  the  manner  first 
described,  then  insert  the  bridge  in  the  mouth,  drill  a  hole  in  the 
spur,  fit  and  cement  in  the  pin,  remove,  invest,  and  solder. 


1  Dr.  S.  S.  Stowell's  method. 


CHAPTER    IV. 

Bar  Bridges. 

incisors     and     cuspids — anchoring     the     bar — bicuspids     and 
molars— an  extension  bar  bridge— gold  inlay  anchorage 

BAR. 

This  style  of  bridge  receives  its  name  from  the  fact  that  the 
teeth  or  dummies  forming  it  are  supported  by  bars  anchored  in 
the  natural  teeth  on  either  side  by  means  of  fillings.  Failure 
to  appreciate  its  limitations,  and  faulty  construction  are  responsi- 
ble for  disappointments  in  its  use  which  have  militated  against  its 
more  common  application. 

In  the  first  place,  its  successful  employment  is  confined  to  the 
insertion  of  one,  or,  at  most,  two  teeth.  An  attempt  to  support 
more  than  two  teeth  by  this  method  will  most  certainly  result  in 
failure. 

The  most  glaring  fault  of  construction  is  insufficient  anchorage 
for  the  bars.  If  the  anchorage  tooth  is  alive,  the  bar  should  ex- 
tend in  a  suitably  shaped  cavity  two-thirds  or  three-fourths  the 

width  of  its  palatal  or  occluding  surface,  ac- 
Fig.  434.  ...  . 

..N  cording  as  it  is  an  incisor  or  a  cuspid,  or  a  bi- 

cuspid or  molar,  and  be  thoroughly  secured  by 
the  filling-material.     Thus  anchored,  the  bar  is 
Ml!  capable  of  supporting  the  bridge  and  resisting 

/  \[\f    \L  -.1  the   leverage   exerted   on   it   in   occlusion   and 

/         :       F   J  mastication,  which  it  cannot  reliably  do  when 

simply  anchored  in  a  shallow  filling  inserted  in 
the  side  of  a  tooth, — an  incorrect  method  too  often  practiced. 

In  a  pulpless  tooth  the  bar  should  be  bent  and  inserted  into  the 
root-canal,  as  shown  in  Fig.  434. 

Incisors  and  Cuspids. — In  the  incisors  and  cuspids  the  anchor- 
age cavities  or  slots  are  formed  in  the  palatal  portion  of  the  teeth, 
extending  from  the  approximal  surface  contiguous  to  the  space  to 
be  bridged,  two-thirds  to  three-fourths  the  width  of  the  tooth,  and 
usually  about  one-third  of  its  length  from  the  gingival  margin 
224 


BAR  BRIDGES.  225 

(Fig.  435),  direct  access  into  the  cavities  being  afforded  through 
the  palatal  wall.  The  slots  or  cavities  having  been  formed,  a 
model  of  the  case  is  made.  Should  the  cavities  to  receive  the  bar 
be  imperfectly  represented  on  the  model,  they  should  be  trimmed 
and  shaped  to  correspond  to  those  in  the  mouth.  The  exact  align- 
ment of  the  porcelain  tooth  in  the  mouth  having  been  determined 
with  the  aid  of  wax,  it  should  be  adjusted  on  the  model  and  secured 
in  position  by  a  matrix  of  plaster. 

The  base  of  the  tooth  should  rest  firmly  on  the  gum,  to  accom- 
plish which  a  small  portion  of  the  plaster 
should  be  removed  from  underneath  the  FlG-  435- 

tooth  on  the  model.  i^jjjffl     A 

The  bar  is  best  constructed  of  plati-  LLlJ   "** 

mini  wire,  Xos.  14  to  16  gage.     Plati-         •F^^/ 
ii i mi  is  preferred  to  iridio-platinum,  be-  '       "M 

cause  it  is  easier  of  manipulation.     The         /P-'  vt£'  / 

wire  can  be  extended  in  one  piece  en-      J\9^~~ jt^=J 
tirelv  across  the  bridge  from  one  anchor-     [jf^^ 
age  to  the  other  by  bending,  or  by  re-     V^ 
moving  a  portion  of  its  bulk  back  of  the 

porcelain  tooth;  <>r  the  bar  can  be  cut  and  made  in  two  sections,  if 
the  position  of  the  anchorage  cavities  so  suggests. 

The  ends  of  the  bar  should  be  flattened  with  a  hammer,  an- 
nealed, and  shaped  as  shown  at  A,  Fig.  435.  The  remainder  of 
the  section  of  the  bar  which  is  to  rest  in  the  cavity  is  best  filed 
on  the  sides,  so  as  to  give  it  a  somewhat  triangular  form,  the 
broad  base  of  which  is  toward  the  bottom  of  the  cavity.  This 
form  favors  the  ready  impaction  of  the  filling-material  which  is 
to  secure  the  bar. 

The  porcelain  tooth  having  been  backed,  the  liar,  whether  in 
one  piece  or  two  sections,  is  attached  to  it  with  wax  cement,  then 
removed  from  the  model  and  soldered.  Enough  gold  should  be 
added  to  properly  contour  the  tooth  and  securely  fasten  the  bar. 

Anchoring  the  Bar. — Gold  and  amalgam  are  the  only  filling- 
materials  suitable  for  securing  bars.  Amalgam  is  objectionable 
only  when  the  position  of  the  cavity  renders  it  visible.  Under 
such  circumstances,  however,  the  exposed  portion  can  be  cut  away 
when  set,  and  covered  with  gold.  Fastening  one  end  of  the  bar 
temporarily  with  oxyphosphate,  while  the  other  is  being  secured, 
will  sometimes  facilitate  the  operation  of  anchoring  with  amalgam. 


226  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

but  the  best  plan  is  to  fasten  the  ends  of  the  bar  with  gold-foil 
pellets  secured  by  pits  drilled  alongside  the  bar,  and  then  fill  flush 
the  remainder  of  the  cavities  with  amalgam.  The  amount  of  gold 
used  need  only  be  sufficient  to  secure  the  bridge  against  the  slight- 
est motion  until  the  amalgam  sets. 

When  the  anchorage  tooth  is  pulpless,  the  end  of  the  bar  which 
extends  into  the  canal  should  be  cemented  first.  Frequently, 
when  bicuspids  and  molars  containing  large  cavities  of  decay  are 
used  for  anchorages,  it  is  advantageous  to  first  insert  the  anchorage 
fillings,  and  then  drill  out  sufficiently  to  admit  the  bar,  which  can 
then  be  secured  with  additional  filling-material. 

When  gold  is  the  filling-material  used,  the  rubber-dam,  which 
must  be  thin,  is  first  adjusted  on  the  natural  teeth,  and  the  bridge 
then  pressed  to  position  over  it.  In  anchoring  with  gold,  the  best 
way  is  to  first  fill  such  portions  of  the  cavities  as  are  inaccessible 
when  the  bars  are  in  position,  how  far  to  proceed  being  determined 
by  occasionally  trying  in  the  piece  as  the  gold  is  inserted.  The 
bridge  is  then  pressed  to  place,  and  held  firmly  while  the  ends 
of  the  bars  are  secured  by  condensing  around  them  a  few  pellets 
of  foil,  after  which  the  gold  is  carefully  impacted  around  the 
bar,  the  filling  of  one  of  the  cavities  being  carried  to  completion 
before  going  on  with  the  other. 

In  the  preparation  of  the  cavities,  their  sides  should  be  given 
an  undercut  form  with  strong  edges.  When  only  sufficient  tooth- 
structure  has  been  removed  at  the  approximal  portion  to  just  ad- 
mit the  bar,  it  is  a  doubtful  experiment  to  attempt  to  fill  the 
narrow  seam  around  it  with  gold.  In  such  cases,  this  portion  of 
the  filling  is  better  made  with  amalgam,  which  is  inserted  at  the 
sides  and  along  the  floor  of  the  cavity  before  the  bridge  is  fixed  in 
position.  Then,  beginning  at  the  interior  end  of  the  cavity,  gold 
can  be  inserted  and  gradually  condensed  toward  the  amalgam, 
with  which  it  will  unite  when  brought  in  contact.  Any  surplus  of 
amalgam  can  be  removed  subsequently  when  it  has  set.  Amalgam 
placed  around  the  bar  as  here  described  is  seldom  visible  from  the 
labial  side,  and  the  quantity  required  is  insufficient  to  materially 
discolor  the  tooth. 

Bicuspids  and  Molars. — In  bicuspids  and  molar  bar  bridges 
the  bar  should  be  carried  well  across  the  occluding  surface,  and 
the  end  bent  and  imbedded  in  the  line  of  the  sulcus  toward  the  side 
opposite  to  that  from  which  the  bar  enters,  as  shown  in  Fig.  436. 


BAR  BRIDGES. 


22' 


Fig.  436. 


^■tfe^^j 


Forming  the  end  of  the  bar  in  this  way  affords  the  greatest  secur- 
ity,  when  it  is  properly  anchored  with   the  filling-material,   by 
preventing  any  rotatory  movement, 
or   any   loosening   of   the  bar   by 
force  applied  in  a  forward  direc- 
tion. 

The  principles  involved  and  the 
method  described  for  shaping  and 
securing  the  ends  of  bars  apply 
equally  well  to  cases  where  one  end 
of  the  bridge  is  supported  by  a  bar 

and  the  other  by  an  artificial  crown,  as  has  been  previously  illus- 
trated. 

An  Extension  Bar  Bridge.. — In  this  form  of  bridge  the  artifi- 
cial (dummy)  tooth  is  supported  by  a  bar  anchored  in  a  natural 
tooth  at  one  end  only.  At  the  other  end  of  the  bridge  the  bar  is 
either  made  in  the  form  of  a  spur  to  rest  against  the  adjoining- 
natural  tooth,  or  it  is  not  extended  beyond  the  dummy. 

In  the  case  represented  in  Fig.  437,  an  upper  cuspid,  the 
patient,  a  lady,  declined  to  have  the  bicuspid  capped  or  crowned 
in  any  way  for  the  purpose  of  support- 
ing the  cuspid.  The  distal  side  of  the 
bicuspid  at  the  time  contained  a  large 
filling.  This  filling  was  removed,  and 
a  cavity  of  proper  shape  to  receive  a 
bar  was  extended  forward  from  it  be- 
tween the  cusps  to  the  mesial  side.  A 
suitable  bar  for  the  cavity  was  formed 
to  support  the  cuspid  in  the  manner  illustrated  at  A  and  B.  The 
angular  form  (C)  given  the  bar  rendered  it,  when  anchored  with 
the  filling-material,  very  secure,  and  fully  capable  of  supporting 
the  cuspid. 

The  filling-material,  which  was  gold,  occupied  most  of  the 
space  of  the  occluding  surface  between  the  cusps.  The  occluding 
tooth  was  trimmed  off  proportionately.  A  spur  extended  from  the 
anterior  side  of  the  artificial  tooth  resting  on  the  lateral  incisor. 
The  occlusion  was  favorable  to  the  insertion  of  the  bridge  tooth 
in  the  form  presented,  and  it  had  been  comfortably  and  satis- 
factorily worn  for  ten  years  when  last  seen.  When  examined  it 
showed  no  change,  except  that  the  force  of  occlusion  on  the  cuspid 


Fig.  437. 


228  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 

had  slightly  bent  the  bar  and  caused  the  tooth  to  assume  a 
slightly  deeper  position  in  the  jaw.  In  some  instances  the  bar 
of  a  bridge  of  this  kind  can  be  extended  across  the  occluding  sur- 
faces of  two  teeth,  and  additional  support  thus  obtained.  (See 
page  235.) 

Gold  Inlay  Anchorage=Bar — Frequently  a  solid  gold  inlay 
formed  of  a  shape  approximating  an  anchorage-bar,  that  fits  a 
correspondingly  shaped  cavity  or  slot  in  a  natural  tooth,  as  illus- 
trated at  N,  Fig.  437  a,  or  in  a  gold 
crown,1  as  shown  at  Gr,  can  be  used 
to  advantage  as  a  support  for  bridge- 
work.  The  cavity  or  slot  is  first 
formed  slightly  dovetail,  with 
straight  sides  flaring  a  little  toward 
the  margin,  and  with  a  depth  pro- 
portioned to  the  width.  The  cav- 
ity or  slot  should  be  so  positioned  as  to  permit  proper  adjustment 
of  the  bridge. 

The  matrix  to  form  the  bar  is  made  by  adapting  1/1000  plat- 
inum to  the  cavity  or  slot  in  the  natural  tooth  or  metal  crown  in 
the  same  manner  as  for  a  porcelain  inlay,  described  in  Part  IV, 
Chapter  V.  The  matrix,  after  having  been  adapted,  is  filled  with 
wax,  a  piece  of  iridio-platinum  wire  inserted  into  the  wax,  and 
the  matrix  removed  and  invested.  The  wax  having  been  removed 
with  boiling  water,  the  matrix  is  filled  with  22-carat  gold  plate, 
applying  the  heat  for  fusing  it  mostly  under  the  matrix.  Zinc 
phosphate  is  required  to  securely  anchor  an  inlay  anchorage-bar 
unless  the  other  end  of  the  bridge  is  supported  by  a  collar,  when 
gutta-percha  may  be  used.  Drilling  a  hole  in  the  seam  at  one  or 
both  sides  of  an  anchorage-bar, — one-half  in  the  crown,  the  other 
in  the  bar,  as  shown  at  H  H,  Fig.  437  a,  and  then  filling  it  solidly 
with  cohesive  gold,- — will  additionally  fasten  or  key  it  in  place. 
When  zinc  phosphate  is  used  it  will  also  prevent  displacement 
while  the  cement  is  setting. 

The  practical  application  of  bar  bridge- work  is  limited,  although 
it  affords  advantages  for  artificial  restoration  not  presented  by 
other  methods  in  many  cases  where  a  single  tooth  has  been  lost. 
Its  practical  success  depends  chiefly  upon  the  character  of  its 
supports  and  the  skilfulness  with  which  it  is  anchored. 

1  Formation  of  a  slot  in  a  gold  crown  is  described  on  pages  205  and  308. 


CHAPTER    V. 

Partial  Cap  and  Pin  Bridge. 

construction— limitations— advantages  of  the  method  in  cases 
with  tulpless  teeth. 

Thts  style  of  bridge  is  used  only  in  case  of  loss  of  a  single  front 
tooth. 

Fig.  43S  represents  a  typical  case,  in  which  a  lateral  incisor 
(crown  and  root)  had  been  lost,  the  cuspid  and  central  incisor, 
fully  vitalized,  and  without  approximal  carious  cavities,  remain- 
ing in  position. 

Construction.1 — 1.  Take  an  accurate  impression  in  plaster. 
From  this  obtain  a  plaster  model  of  the  parts. 

Fig.  43S. 


2.  Make  from  pure  gold,  rolled  to  the  thinness  of  jSTo.  2S 
gage,  base-plates,  to  be  carefully  adjusted  to  the  palato-approximal 
surfaces  of  the  cuspid  and  incisor.  These  can  be  made  by  swaging 
on  dies  and  counter-dies  obtained  from  the  model,  but  more  con- 
veniently by  bending  the  gold  into  shape  upon  the  plaster  model 
and  pressing  and  burnishing  it  into  perfect  adaptation  upon  the 
natural  teeth. 

3.  Select  a  plain  plate  porcelain  tooth  of  suitable  length  that 
will  fit  easily  into  the  interspace;  back  with  gold  or  platinum; 
adjust  in  position  to  the  gold  base-plates  on  the  model,  and  attach 


1  Dr.  W.  F.  Liteh.  Dental  Cosmos,  vol.  xxviii.  No.  3. 


229 


230 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


with  wax  cement.  Remove  and  fit  in  the  mouth,  and  chill  with 
ice-water.  Next  remove  from  the  mouth,  invest,  and  solder  tooth 
and  plates  together,  as  shown  in  Fig.  439. 

4.  For  attaching  the  denture  as  thus  far  constructed,  drill  a 
small  cylindrical  opening  through  the  palatal  surface  of  the 
enamel  of  the  cuspid  and  incisor  respectively.  These  openings 
should  usually  be  placed- about  as  indicated  in  Fig.  441,  at  C  I). 


Fig.  439. 


Fig.  440. 


Sometimes,  owing  to  a  close  occlusion  or  to  the  contour  of  the 
tooth,  it  is  desirable  that  they  should  be  located  a  trifle  nearer  the 
neck  of  the  tooth.  Each  opening  should  be  well  undercut,  but 
must  not  encroach  upon  the  dentin  far  enough  to  endanger  the 
pulp.  In  size  the  openings  need  not  be  larger  than  will  admit  a 
platinum  pin-head,  in  diameter  corresponding  to  No.  13  gage,  with 
a  shank  of  No.  18  gage.  Into  each  of  these  openings  must  be 
fitted  a  platinum  pin  of  the  size  indicated.     The  head  of  each  pin 


PARTIAL  CAP  AXD  PIX  BRIDGE.  231 

must  be  made  thin  and  perfectly  flat  both  upon  its  upper  and 
under  surfaces. 

5.  In  each  of  the  base-plates  make  an  opening  corresponding  in 
position  to  those  in  the  natural  teeth.  Pass  through  these  openings 
and  cement  in  them  the  free  ends  of  the  platinum  pins.  While 
the  cement  is  vet  plastic,  place  the  denture  in  position  in  the 
mouth,  carefully  pressing  the  pin-heads  into  the  openings  made 
for  them,  and  burnishing  the  base-plates  into  perfect  contact  with 
the  palatal  surfaces  of  the  teeth;  chill  the  cement,  remove,  and 
invest.  Next  attach  the  pins,  and  also  flow  solder  over  the  surface 
of  the  base-plates  to  stiffen  them. 

Fig.  439  represents  the  appliance  without  the  pin.  A  is  the 
porcelain  tooth  and  backing;  E,  the  base-plates;  C  and  F,  the  open- 
ings for  the  pins. 

Fig.  440  represents  the  appliance  completed  with  the  pins  in 
position. 

Fig.  441  represents  the  natural  teeth  and  interspace  B,  with 
openings  C  D  for  retaining-pins. 

Fig.  442  represents  the  appearance  of  the  bridge  when  ce- 
mented in  position.  The  occluding  teeth  should  be  trimmed 
sufficiently  to  leave  a  slight  space  between  them  and  the  caps. 

The  bridge  is  attached  by  cementing  in  position  with  oxyphos- 
phate. 

Limitations. — When  the  supporting  teeth  have  vital  pulps  and 
very  sensitive  dentin,  the  difficulty  of  securing  reliable  anchorage 
for  each  of  the  plates  seriously  militates  against  this  method. 
Loosening  of  the  bridge,  especially  in  "close  bites,"  is  apt  to  occur 
at  the  most  inopportune  moment,  demanding  its  immediate  re- 
cementation.  Practical  experience  by  the  author  in  the  use  of 
this  form  of  attachment  shows  that  three  pins — inserted  as  deeply 
as  possible  without  too  closely  approaching  the  pulp — are  neces- 
sary in  each  of  the  plates. 

Advantages  in  Cases  with  Pulpless  Teeth — This  method  pos- 
sesses considerable  merit  when  the  supporting  teeth  are  pulpless 
and  free  from  decay  or  only  slightly  affected.  A  substantial  post 
introduced  in  the  root-canal  of  either  a  central  or  a  cuspid  will 
be  found  sufficient  to  afford  reliable  support  for  an  adjoining 
artificial  lateral  with  the  addition  of  a  spur  on  the  palatal  surface 
of  the  contiguous  tooth  on  the  opposite  side  of  the  crown,  in- 
dependent of  any  other  attachment. 


232  CROWN-,  BRIDGE-,  AXD  PORCELAIN -WORK 

To  replace  an  absent  superior  lateral,  for  instance,  when  the 
adjoining  cuspid  is  in  normal  condition,  the  extirpation  of  its  pulp 
and  the  application  of  a  support,  such  as  is  described,  will  fre- 
quently be  found  preferable  to  a  method  which  demands  excision 
of  the  natural  crown,  an  operation  to  which  many  patients  would 
strenuously  object. 

Fig.  443  illustrates  a  typical  case  in  which  a  lateral  is  to  be 
artificially  replaced.     In  such  cases  the  cuspid, 
Fig.  443.  being  more  capable  of  giving  the  required  sup- 

port than  the  central,  is  the  proper  tooth  to 
devitalize  and  use  as  the  abutment.  When  the 
pulp  of  a  cuspid  is  removed  by  instantaneous 
extirpation,  or  by  arsenic  used  in  a  judicious 
manner,  very  little  discoloration  of  the  dentin 
and  enamel  is  liable  to  ensue  (see  Part  I,  Chap- 
ter II). 

The  entrance  to  the  pulp-chamber  should  be 
made  well  toward  the  incisal  edge,  so  as  to  be 
in  a  direct  line  with  the  root-canal.  The  orifice  needs  to  be  en- 
larged sufficiently  to  admit  a  substantial  post  and  permit  the 
metal  which  constitutes  the  cap  to  be  depressed  into  the  orifice 
and  around  the  post,  so  that  the  projecting  end  can  be  finished 
off  level  with  the  surface  of  the  cap  yet  have  a  secure  attachment 
to  it. 

To  construct  this  attachment  a  tapering  platinum  post  is  fitted 
well  up  the  canal.  A  disk  of  pure  gold  plate,  jNTo.  30  to  32  gage, 
or  of  platinum,  about  No.  34  gage,  is  adapted  to  the  entire  palatal 
surface  of  the  tooth.  This  is  facilitated  by  first  burnishing  or 
shaping  it  on  a  fusible-metal  die  of  the  tooth.  The  metal  is  then 
to  be  burnished  down  into  the  reamed  orifice  of  the  root-canal,  a 
hole  made  through  the  metal  into  the  canal  and  a  post  fitted 
therein,  waxed  in  position  in  the  metallic  cap,  removed,  invested, 
and  soldered.  In  the  soldering  enough  solder  should  be  flowed  over 
the  surface  of  the  cap  to  strengthen  and  stiffen  it.  The  surplus 
projecting  end  of  the  post  should  usually  be  cut  off  even  with  the 
external  surface  of  the  cap,  but  if  it  does  not  interfere  with  the 
antagonizing  teeth  in  occlusion,  it  may  be  left  extending  from  the 
cavity  or  be  only  partly  removed  during  the  construction.  In  the 
case  of  lower  incisors  and  cuspids,  the  projecting  end  will  afford  a 
means  for  easy  removal  when  in  position  on  the  roots,  especially 
if  an  impression  is  taken. 


PARTIAL  CAP  A~SD  PIX  BRIDGE.  233 

The  cap  and  post  are  next  adjusted  on  the  tooth  and  a  porcelain 
tooth  ground,  fitted  in  position,  and  cemented  with  wax  to  the  cap, 
the  work  removed,  and  the  parts  soldered  together.  The  addition 
of  a  spur  to  rest  in  the  central  is  advisable,  as  illustrated  in  Fig. 
443. 

This  method  of  constructing  abutments  is  applicable  to  more 
■extended  operations,  such  as  the  supporting  of  four  incisors  on 
the  two  cuspids  alone  or  in  conjunction  with  a  central  tooth  or 
root. 


CHAPTER    VI. 

Application  of  Bridge-Work  in  Cases  of  Pyorrhea 
Alveolakis. 

dr.  rhein's  method  of  "splinting" — the  partial  cap  and  pin- 
bridge  method— use  of  connecting  collars. 

In  cases  of  pyorrhea  alveolaris  when  the  teeth  are  very  loose, 
connecting  them  together  with  bridge-work  steadies  them  in  their 
sockets  and  consequently  permits  more  effective  treatment. 


Fig.  444. 


Fig.  445. 


Fig.  446. 


Fig.  447. 


Dr.  Rhein's  Method  of  Splinting — In  these  cases  Dr.  M.  L. 
Rhein  advocates  the  use  of  a  form  of  bridge-work  he  terms  "splint- 
ing." By  the  adoption  of  this  method  the  natural  appearance  and 
shape  of  the  teeth  are  preserved  and  their  hygienic  condition  inter- 
fered with  very  little,  if  any.  The  method  as  applied  to  a  superior 
central  and  cuspid  to  carry  a  lost  lateral  is  shown  in  Fig.  444,  to 
234 


APPLICATION  OF  BRIDGE-WORK  IN  PYORRHEA  ALVEOLARIS.   235 

lower  teeth  in  Fig.  445,  and  to  two  bicuspids  and  a  molar  in  Fig. 
446.  The  pulps  of  the  teeth  in  these  cases  were  removed,  with 
the  exception  of  the  molar,  and  grooves  or  slots  were  cut,  as  shown 
in  Figs.  44G  and  447.  Staples  of  triangular  platino-iridinm  wire 
with  parallel  arms  (Fig.  448)  were  fitted  into  the  individual 
root-canals  of  the  pnlpless  teeth  with  an  extension  added  to  the 
staple  in  the  form  of  a  straight  bar  to  extend  into  the  slot  in  the 
molar.  In  the  case  of  the  artificial  lateral  the  bar  was  carried 
across  the  backing  and  attached  as  shown  in  Fig.  449. 

Dr.  Ehein's  method  of  anchoring  the  bar  and  restoring  r lie  form 
of  the  teeth  in  these  operations  is  to  first  lino  the  circumference 
of  the  outer  plane  of  the  orifice  of  the  pulp-canal  and  the  bottom 
of  the  groove  with  a  thin  gold  filling,  leaving  the  entrance  to  the 

Fig.  4-18.  Fig.  440.  Fig.  450. 


LaJ 


Fig.  451.  Fig.  452.  Fig.  453. 


canals  open  for  the  admission  of  the  pins  of  the  staple.  This  is 
accomplished  by  filling  the  canals  with  cones  of  bibulous  paper 
nearly  to  the  orifice,  then  placing  over  the  bibulous  paper  in  the 
orifice  a  thin  layer  of  oxyphosphate,  and  while  the  cement  is  soft 
gently  patting  into  it  pellets  of  gold.  After  waiting  a  few  minutes 
gold  foil  is  malleted  over  the  entire  inner  surface  of  the  slot  and 
around  the  orifice  of  the  pulp-chamber.  With  a  fissure-bur  en- 
trance to  the  paper  cone  in  the  canal  is  easily  made  and  the  paper 
withdrawn,  leaving  the  canal  open  for  the  admission  of  the  pin, 
as  shown  in  Fig.  450.  The  canals  are  next  filled  with  oxyphos- 
phate,  in  such  amount  as  will  avoid  an  excess,  and  the  pins  of  the 
bar  are  cemented  in  proper  position  (Fig.  451). 

After  the  cement  has  hardened  sufficiently,  the  gold  filling  which 
line  the  groove  in  which  the  staple  lies  is  continued  and  brought 

17 


236 


GROWN-,  BRIDGE-,  AXD  PORCELAIN -WORK. 


up  over  the  sides  of  the  wire,  which  is  ultimately  completely  cov- 
ered by  it,  as  shown  in  Fig.  452.  When  the  gold  is  properly 
finished  with  plug-finishing  burs  and  fine  cuttlefish  disks,  there  is 
no  edge  or  unevenness  present,  as  seen  in  Fig.  453,  which  illus- 
trates a  cuspid  as  it  appears  with  the  protruding  bar. 

The  Partial  Cap  and  Pin=Bridge  Method. — The  partial  cap 
and  pin-bridge  method,  described  in  the  preceding  chapter,   is 


Fig.  454. 

ioosf  tooth 


specially  useful  in  application  to  cases  of  pyorrhea  alveolaris.  By 
this  method  the  loosened  teeth  can  be  joined  together  and  sup- 
ported without  exposure  of  metal. 

In  such  cases  the  pulps  are  removed  from  the  affected  teeth  and 
the  root-canals  treated.      Pins  and  cup-  are  fitted  to  each  tooth, 


Fig.  455. 


the  ends  of  the  pins  being  left  protruding  from  the  caps.  An  im- 
pression is  then  taken,  removing  the  caps  and  pins  in  position. 
They  are  next  invested  and  soldered  together. 

An  intervening  absent  tooth  or  teeth  may  be  supported  between 
sections  of  the  caps. 

The  method  is  specially  applicable  in  cases  involving  the  lower 
front  teeth.     Fig.  454  illustrates  such  a  case  with  the  teeth  pre- 


APPLICATION    OF  BRIDGE-WORK  JX   PYORRHEA  ALVEOLARIS.  237 

pared;  Fig.  455,  the  caps  with  their  projecting  posts  in  position; 
Fig.  456,  the  constructed  denture,  and  Figs.  457  and  458,  the 
denture  in  position  on  the  teeth.1 


Fig.  456. 


Fig.  4 


Use  of  Connecting  Collars — Fig.  459  explains  and  illustrates 
a  method  of  restoring  an  incisor  and  supporting  the  adjoining 
Loosened  teeth  with  successive  cemented  c< nnn.-<-uiiir  collars  of  gold 

Fig.  458. 


in  cases  of  pyorrhea  alveolaris.  For  the  application  of  such  collars 
the  teeth  generally  need  to  be  slightly  separated.  The  collars 
may  be  formed  of  a  strip  of  pure  gold  plate,  about  Xo.  32  to 


Fig.  459. 


33  gage,  by  bending  and  fitting  the  strips  to  the  forms  of  any  two 
teeth,  in  the  shape  shown  in  Fig.  460,  A.  This  leaves  but  one 
thickness  of  the  plate  between  the  teeth.     An  additional  loop  can 


Dr.  D.  D.  Smith. 


238  CROWN-,  BRIDGE-,  AND  PORCELAIN  -WORK. 

then  be  added  as  shown  at  B,  for  one  adjoining  tooth.  All  the 
soldering  can  be  done  quickly  with  the  Bunsen  burner  without  in- 
vesting. Parts  of  the  loops  which  demand  it  should  be  slit  and 
lapped,  to  permit  the  gold  to  be  brought  close  to  the  surface  of 
the  tooth. 

The  bands  of  metal  should  be  adjusted  towTard  the  incisal  section 
of  the  teeth,  leaving  the  inter-approximal  spaces  between  the  teeth 
entirely  free.  The  cementation  can  be  done  with  zinc  phosphate, 
or  gutta-percha  cement  if  removal  is  contemplated. 


CHAP  TEE    VII. 

Removable  axd  Replaceable  Porcelain  Fronts. 

purpose  of  their  use— modification  of  dr.  wardwell's  method 
— dr.  van  woert's  pliers  and  "mason's  detachable  tooth"— 
a     simple     form— dr.     alexander's     method— dr.     bryants 

.METHOD. 

Removable  porcelain  fronts  are  used  to  avoid  the  risk  of  frac- 
turing the  porcelain  in  the  operation  of  soldering,  but  principally 
to  permit  their  more  easy  replacement  in  case  of  fracture.  The 
replacing  of  a  porcelain  front  after  the  work  has  been  permanently 
fixed  in  position  is  frequently  attended  with  great  difficulty,  and 
the  result  is  often  unsatisfactory  or  doubtful  regarding  its  per- 
manency. The  desire  to  obviate  such  difficulties  has  prompted 
the  introduction  of  various  methods  of  construction  in  which  the 
porcelain  fronts  are  removed  from  their  positions  previous  to  the 
soldering  processes,  and  afterward  adjusted  so  as  to  be  easily  re- 
placeable by  means  of  duplicates  in  case  of  fracture  when  the 
work  is  being  worn  in  the  mouth.  These  methods  applied  to  a  bar 
bridge  afford  access  to  the  cavities  of  anchorage. 

Dr.  I.  F.  Wardwell's  Method — A  modification  of  Dr.  I.  F. 
Wardwell's  method,  which  is  simple  in  construction  and  applica- 
tion, is  as  follows:  A  thick,  narrow  piece  of  18-carat  gold  plate, 
;it  least  No.  18  standard  gage,  is  soldered  to  the  tooth,  and  its 
two  sides  undercut  with  a  vevy  thin  separating  tile  (Figs.  461, 
462  ).  A  very  thin  piece  of  platinum,  covering  the  entire  back  of 
the  tooth,  is  burnished  against  it,  well  into  the  undercut  sides,  the 
platinum  being  annealed  several  times  during  the  operation.  The 
platinum  is  held  in  a  flame  while  a  small  quantity  of  pure  gold 
is  flowed  over  the  outer  surface  and  then  refitted  to  the  back  of 
the  tooth,  to  which  it  is  again  burnished.  This  operation  is  re- 
peated until  the  platinum  and  gold  form  a  moderately  light  back- 
ing which  fits  perfectly.  The  platinum  surface  is  then  covered 
with  investing  material,  and  on  the  other  side  IS-  or  20-carat 
gold  plate  flowed  until  a  suitable  thickness  is  obtained.  When 
trimmed  into  proper  shape  and  attached  to  a  bar  or  a  bridge,  this 
forms  a  substantial  backing  or  socket  (Fig.  463),  in  which,  when 

239 


240 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


the  bridge  is  finished  or  the  bar  anchored,  the  porcelain  tooth  can 
be  fastened  with  a  little  zinc  phosphate  or  gutta-percha  cement 
(Fig.  464).  Dr.  F.  T.  Van  "Woert  has  introduced  pliers  with  com- 
bination points  which  much  simplify  the  construction  of  a  socket 
of  this  form  and  the  replacement  of  the  porcelain  front  in  case  of 
fracture  by  the  patient.1  Owing  to  the  manner  in  which  this  style 
of  removable  front  is  inserted  in  its  socket,  it  does  not  admit  of 
protection  of  the  incisal  edge,  and  is  consequently  much  more 
liable  to  fracture  than  one  which  is  properly  protected. 


Fig.  461.       Fig.  462. 


Fig.  463. 


Fig.  464. 


Fig.  465. 


A  Simple  Form. — Any  ordinary  porcelain  front  to  a  bicuspid 
or  molar  dummy  can  be  made  on  the  removable  or  replaceable 
plan,  by  backing  the  porcelain  in  the  usual  manner  with  gold  or 
platinum  plate  without  bending  the  pins,  adjusting  the  gold  cap  in 
position,  attaching  the  cap,  and  backing  with*  wax  cement,  then, 
removing  the  porcelain  front  (Fig.  465),  investing  and  soldering 
the  cap  and  backing  together.  The  backing 
must  be  made  thick  with  solder,  the  holes  in  it 
deepened  with  a  drill,  and  the  pins  of  the  porce- 
lain front  serrated  and  fitted  therein.  After  the 
final  soldering,  the  porcelain  fronts  are  cemented 
in  position  with  oxyphosphate.  This  method, 
though  affording  sufficient  attachment  for  a 
short  molar,  such  as  is  illustrated  in  Fig.  465,  is 
suggestive  of  insecurity  for  most  of  the  front 
teeth. 

Dr.  Alexander's  Methods — Dr.  C.  L.  Alexan- 
der's method  is  to  use  teeth  having  long  pins,  as  in  Fig.  466.  The 
facings  are  fitted  in  proper  position  and  cemented  with  hard  wax. 

Porcelain  fronts  or  dummies  of  the  character  described  with  the  backing 
baked  in  the  porcelain  of  the  tooth  can  now  be  purchased  ready-made  under 
the  name  of  "Mason's  Detachable  Tooth." 


Fig.  466. 


REMOVABLE  AND  REPLACEABLE  PORCELAIN  FRONTS.       241 


The  wax  around  the  pins  is  then  heated  with  the  point  of  a  hot 
instrument,  and  the  facings  are  removed  without  disturbing  the 
backings.  Half-inch  pieces  of  fine  iron  binding-wire  are  bent  to 
form  staples,  their  ends  heated  and  pushed  through  the  pin-holes 
from  the  facing  side  in  the  backings,  leaving  a  loop  on  that  side 
and  projecting  ends  on  the  other,  which  are  twisted.  The  wax  is 
removed  from  the  I  lacking  and  little  ferrules  of  pure  gold  placed 
around  the  pin-holes  (  Fig.  467).    Hard  wax  is  next  applied  on  the 


Fig.  467. 


Fig.  468. 


outside  of  the  ferrules,  the  ends  of  the  iron  wire  brought  down  to 
hold  them  in  position,  and  the  inside  of  the  ferrules  filled  with 
investing  material.  Fig.  468  shows  an  invested  case  ready  for  the 
soldering  process,  which  will  unite  the  ferrules  to  the  backings, 

Fig.  469. 


and  at  the  same  time  join  the  backings  to  each  other  and  properly 
shape  them.  "When  soldered  and  trimmed,  the  facings  are  put  in 
place  with  a  very  thin  oxyphosphate  cement  between  fronts  and 
backings,  the  pin  ends  are  bent  down  on  the  backing  within  the 
ferrules,  and  the  ferrules  filled  with  amalgam  packed  moderately 
dry.  The  bridge  is  then  put  aside  until  the  amalgam  has  set,  when 
it  is  ready  for  insertion.     Fig.  469  shows  a  central  crown  ready  to 


242  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

receive  the  porcelain  front,  and  a  piece  of  bridge-work  with  the 
cuspid  ferrule  chambers  as  yet  unfilled. 

Dr.  E.  A.  Bryant's  Method — This  differs  from  that  just  de- 
scribed in  that  the  space  between  the  two  pins  of  the  tooth,  as 
they  project  straight  out  from  the  porcelain,  is  first  filled  in  with 
soft  solder  so  as  to  unite  the  pins  and  form  an  oval-shaped  flat- 
ended  flange.  The  backing  is  made  with  a  box  to  accommodate 
this  flange,  and  into  this  when  attached  the  flange  is  cemented. 


CHAPTER    VIII. 

General  Application  of  Crown-  and  Bridge- Work. 

central  or  lateral  incisors,  cuspids  or  bicuspids— centrals, 
laterals,  or  cuspids  combined— cuspids,  bicuspids,  and 
molars  combined— bicuspids  and  molars  combined:  use  of 
partial  cap— incisors.  cuspids,  bicuspids,  and  molars  com- 
BINED. 

The  construction  and  general  application  of  bridge-work,  as 
explained  in  the  foregoing  chapters,  are  additionally  explained 
and  illustrated  in  applying  them  to  the  following  typical  cases : 

Central  or  Lateral  Incisors,  Cuspids  or  Bicuspids. — Figs.  470 
and  471   illustrate  a   method  of  replacing  a  superior  central  or 

Fig.  470.  Fig.  471. 


lateral.  The  central  or  lateral  is  formed-with  a  base  of  gold  or 
platinum  resting  closely  on  the  gum.  A  gold  cap-crown  on  the 
first  bicuspid  is  used  to  support  it  in  position  by  means  of  an 
iridio-platinum  bar.  A  small  spur  placed  on  the  mesial  side  of  the 
bridge-tooth,  and  resting  on  the  central,  is  suggested  in  such  cases. 
Figs.  472  and  473  show  a  case  in  which  two  centrals  are  sup- 
ported in  position  by  bars  extending  from  gold  crowns  on  bicus- 
pids. The  method  of  construction  in  these  cases  is:  First  cap  the 
bicuspids ;  then  fit  and  back  the  bridge-tooth  or  teeth  and  fasten 
in  position  in  the  mouth  with  hard  wax.  Next  take  a  plaster  im- 
pression. Remove  and  make  plaster  and  marble-dust  model,  show- 
ing teeth  and  crowns  in  position.  Mark  and  slightly  groove  the 
line  of  the  bar  on  the  model.    Fit  the  bar  in  position  in  the  groove, 

243 


244 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


and  wax  the  ends  to  cap  and  tooth.  Fasten  the  center  of  the  bar 
and  cover  the  teeth  and  caps  with  investing  material,  and  solder 
bar  or  bars  and  cap  or  caps  together;  spurs  resting  on  the  laterals 
may  also  be  applied. 

Figs.  474  and  475  illustrate  a  method  of  construction  which  will 


Fig.  472. 


Fig.   473. 


avoid  the  exposure  of  gold,  and  also  the  pressure  of  a  bar  against 
the  membrane  of  the  gum.  A  shell  crown  is  constructed  as  de- 
scribed on  page  212,  Fig.  405,  for  the  bicuspid.  The  crown  is 
placed  on  the  tooth,  the  lateral  adjusted  and  cemented  in  position, 


Fig.  474. 


Fig.  475. 


an  impression  taken,  and  a  model  made  as  described  in  the  con- 
struction of  case  illustrated  by  Figs.  470  and  471.  With  the 
crown  and  lateral  in  position  on  the  model,  a  narrow  strip  of  thin 
platinum  plate  is  fitted  across  the  palatal  side  of  the  cuspid,  touch- 
ing the  gold  crown  and  backing  of  the  lateral.     Over  the  platinum 


GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE-WORK.       245 


is  placed  a  still  narrower  piece  of  gold  plate  (clasp-gold  preferred). 
These  are  waxed  at  the  ends  to  the  cap  and  lateral,  and  held  in 
position  in  the  center  with  investing  material.  When  the  ends 
have  been  attached  with  the  solder  to  the  crown  and  lateral,  the 
investing  material  is  removed  from  the  center  and  the  solder  is 
then  flowed  across  the  bar.  This  forms  a 
bar  with  a  surface  of  platinum  to  resl 
against  the  tooth. 

Fig.  476  shows  a  form  of  -bridge-work 
suitable  for  the  replacement  of  one  or  Two 
inferior  incisors.  The  labial  section  of  the 
shell  crowns  which  form  the  support  for 
the  artificial  tooth  should  be  removed  only 

enough  to  avoid  any  considerable  exposure  of  the  gold  in  the 
movement  of  the  lips. 

Other  cases  illustrating  methods  for  single  centrals  and  laterals, 
cuspids  and  bicuspids,  are  shown  in  Figs.  404,  419,  421,  423,  430, 
434,  437,  437  a,  443,  447,  and  464. 


Fig.  477 


Fig.  478. 


Centrals,  Laterals,  or  Cuspids  Combined Two  laterals  sup- 
ported by  two  central  crowns  are  illustrated  in  Figs.  477  and  47S. 
Spurs  might  be  additionally  formed  on  the  laterals  to  rest  on  the 
cuspids.  When  approximal  crowns,  as  in  this  case,  are  united  to 
support  bridge-work,  a  free  space  should  be  preserved  at  the  neck 
between  their  respective  collars  to  admit  the  gum-septa. 


246 


CROWN-,  BRIDGE-,  AND   PORCELAIN-WORK. 


Figs.  479,  480,  481,  and  4S2  show  a  bridge  of  the  incisors  sup- 
ported by  two  collar  crowns  on  the  cuspid  roots.  Shell  crowns 
can  also  be  used  for  this  purpose,  according  to  the  preference  of 
the  operator.  Figs.  483,  484,  and  485  illustrate  a  case  with  shell 
crowns  for  supports.     In  its  construction  the  best  method  of  pro- 


Fig.  479. 


'A 


cedure  is  to  form  and  fit  the  caps  or  crowns  to  the  cuspids,  re- 
move them  in  plaster  impression  and  bite,  make  models,  and 
then  bridge  between  the  shell  caps  or  crowns  with  the  incisors. 
The  edges  of  the  collars  of  these  shell  caps  should  be  beveled 
and  burnished  close  to  the  teeth.      If  properly  done  they  will 


Fig.  4S0. 


Fig.  481. 


resemble  gold  fillings.  When  these  shell  caps  become  loose  from 
disintegration  of  the  cement  they  should  be  immediately  reset. 
It  would  be  well  if  cases  of  this  style  could  be  removed  once  a 
year  and  re-cemented.  Gutta-percha  cement,  alone  or  used  in 
combination   wLth   zinc   oxyphosphate,    by   covering   the   natural 


GENERAL  APPLICATION  OF  GROWN-  AND  BRIDGE  WORK.       247 

crowns  with  a  film  of  oxyphosphate  mixed  thin  just  before  the 
final  insertion  of  the  bridge,  with  the  heated  gutta-percha  in  the 
caps,  is  to  be  recommended  for  these  cases.  Other  cases  of  this 
character  are  illustrated  in  Figs.  370,  393,  and  459. 


Cuspids,  Bicuspids,  and  Molars  Combined. — Figs.  486  and 
487  show  bridge-work  supported  by  cuspid  and  molar  cap  or 
crown.     If  the  cuspid  contains  a  living  pulp,  the  natural  crown 

Fig.  483. 


should  be  preserved,  and  an  all-gold  or  shell  crown  should  be  used 
in  preference  to  the  form  illustrated,  or  the  pulp  should  be  de- 
stroyed and  a  partial  cap  with  a  long  pin  inserted  in  the  canal. 
Figs.  403  and  433  illustrate  other  cases. 


248 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


Bicuspids  and  Molars  Combined:  Use  of  Partial  Cap. — Fig. 
488  represents  a  bridge  on  the  lower  jaw  from  the  first  bicuspid  to 
the  second  molar.  The  inclination  of  the  teeth  toward  each  other 
suggests  the  construction  of  the  bridge  in  the  form  illustrated. 


Fig.  484. 


Fig.  485. 


The  molar  is  covered  entirely  with  a  cap,  the  bicuspid  only  on  the 
occlusal  surface,  with  the  gold  extending  about  half  down  the 
coronal  section  of  the  natural  crown  (A  ).  A  pin  inserted  in  the 
cap  fitting  a  hole  drilled  in  the  sulcus  of  the  occluding  surface  of 

Fig.  486. 


the  bicuspid  will  secure  this  cap  in  position.  This  method  is  very 
suitable  to  a  case  where  the  crown  of  the  bicuspid  is  long  and  the 
root  slightly  exposed.  Molars  under  similar  circumstances  can  be 
capped  for  bridge-work  in  like  manner. 


GENERAL  APPLICATION  OF  GROWN-  AND  BRIDGE-WORE.       249 

Fig.   489   illustrates  a   case  of  bridge-work  supported  on   an 
abraded  bicuspid  and  molar  by  partial  caps  or  gold  "tips"  with 


Fig.  487. 


Fig.  4S8. 


Fig.   4S9. 


pins,  the  construction  of  which  is  described  on  page  157.     It  will 
be  noticed  that  the  molar  tips  forward  considerably. 


250 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  490  represents  a  practical  case  in  which  the  upper  third 
molar  and  the  first  bicuspid  were  utilized  for  the  attachment  of  a 
bridge,  to  supply  the  loss  of  the  intervening  teeth.1 


Fig.  490. 


Fig.  491  represents  the  case  as  prepared  for  the  bridge.     A, 
the  inner  cusp  of  the  bicuspid  cut  clown  to  allow  the  placing  of 


Fig.  491. 


D--. 


~~JUUMulillllLi.ililiiili!ll^ 

Fig.  492. 


a  sufficiently  thick  crown-plate;  B,  a  cylindrical  undercut  open- 
ing between  the  cusps  for  a  retaining-pin;  0.  the  third  molar, 
made  uniform  in  size  from  neck  to  grinding-surface,  the  latter 

1  Dr.  W.  F.  Litch. 


GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE  WORK.       251 

also  being  considerably  retrenched;  D,  a  partial  cap,  so  constructed 
as  to  cover  every  portion  of  the  tooth  except  its  buccal  surface, 
the  free  edge  passing  up  under  the  gum;  E,  a  retaining-piu  adapted 
to  the  opening  B;  F,  the  gold  cap  for  the  molar. 

Fig.  492  represents  the  bridge  anchored  in  position  with 
cement. 

Fig.   493  represents  another  case  in  which  a  bridge  was  at- 

Fig.  493. 


tached  by  a  bar,  partial  cap,  and  retaining-pin.  A  is  an  upper 
second  bicuspid  (without  antagonist) ;  B,  its  inner  cusp,  cut  down ; 
C,  opening  for  retaining-pin;  D,  second  molar,  with  slot  for  bar; 
E,   cuspid;   F  represents  the  partial   cap;    G,   the   retaining-pin; 


Fig.  494. 


H,  a  molar  tooth  of  gold,  with  porcelain  front;  I,  a  platinum  bar 
attached  to  the  tooth  H  and  made  to  fit  into  a  slot  at  D;  J, 
a  plain  plate  cuspid,  heavily  backed  and  strongly  soldered  to  the 
partial  cap,  but  left  without  attachment  to  or  contact  with  the 
cuspid. 

Fig.  494  shows  the  bridge  anchored  in  position. 

As  the  gold  attachments  and  backings  were  out  of  sight,  the  ap- 
18 


252 


GROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 


pearance  presented  was  natural.  There  is  this  fact  to  be  considered 
in  regard  to  the  use  of  the  partial  caps,  that  many  patients  can  be 
induced  to  consent  to  their  employment  who  would  refuse  to  sub- 
mit to  more  radical  measures,  and  thus,  even  when  the  latter  would 
be  advisable,  the  former  may  be  employed  as  a  compromise,  or 
even  as  a  temporary  expedient.    Having  once  tested  the  advantage 


Fig.  495. 


Fig.  496. 


of  a  well-fitting  bridge,  at  some  future  time  the  wearer  is  much 
more  likely  to  consent  to  whatever  measures  are  necessary  to  give 
it  security  and  permanence^ 

Incisors,  Cuspids,  Bicuspids,  and   Molars  Combined. — Figs. 
495  and  496  represent  a  piece  of  bridge-work  extending  from  a 

Fig.  497. 


central  incisor  to  a  molar.  In  such  a  case  the  best  method  of  pro- 
cedure usually,  and  specially  the  one  most  likely  to  prevent  misfit 
from  warping,  is  to  construct  the  front  section,  consisting  of  the 
central,  lateral,  and  cuspid,  first.  Xext  form  the  molar  cap,  fit  it 
with  the  front  section  of  the  bridge  in  position  in  the  mouth, 
remove  in  plaster  impression  and  bite,  and  construct  the  bicuspid 


GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE  AY  ORK.       253 

and  molar  dummies  between  the  cuspid  crown  and  molar  crown. 
In  a  bridge  of  this  character,  if  the  natural  cuspid  is  intact,  a 
shell  crown  may  be  used.     Fig.  497  gives  the  palatal  view  of  a 

Fig.  498. 


piece  of  bridge-work  consisting  of  a  gold  cap  on  the  molar  and 
shell  cap  on  the  crown  of  the  cuspid,  supporting  a  single  bicuspid 
and  a  lateral  incisor. 


Fig.  499. 


Extensive  Applications  of  Crown-  and  Bridge-Work. 

The  following  illustrations  of  cemented  bridge-work,  by  Dr. 
H.  A.  Parr,  show  extreme  cases  in  the  way  of  large  operations 
in  which  the  system  has  been  applied : 


254 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Figs.  498,  499,  500,  and  501  represent  a  case  in  which  the 
roots  of  the  two  superior  centrals,  a  partially  decayed  right  first 
molar,  and  a  badly  decayed,  pulpless  left  first  molar  were  all  that 
remained  of  the  upper  natural  teeth.  On  the  two  central  roots 
were  mounted  collar  crowns,  and  on  the  two  molars  all-gold  cap- 

Fig.  500. 


crowns.  These  four  crowns,  acting  as  abutments  for  the  bridge 
denture,  bore  between  them,  proportionately  on  each  side,  the 
force  and  leverage  of  occlusion.  The  contour  of  the  arch  in  the 
region  of  the  cuspids  was  restored  by  a  skilful  and  artistic  placing 
of  the  artificial  teeth,  which  are  prominent  and  long. 


Fig 


Figs.  502,  503,  504,  and  505  represent  a  case  in  which  two 
large  and  firm  superior  cuspid  roots,  and  a  right  pulpless  molar, 
with  a  saddle  on  the  left  side,  support  a  large  bridge. 

In  the  case  illustrated  by  Figs.  506  and  507,  two  superior  molars 
and  a  second  bicuspid  on  the  right,  and  a  first  bicuspid  and  a  saddle 


GENERAL  APPLICATION  OF  CROWN-  AXD  BRIDGE-WORK.       255 

under  the  ''dummy"  representing  the  first  molar  on  the  left  side, 
form  the  abutments.  Prior  to  the  insertion  of  the  bridge-work. 
the  patient  had  worn  artificial  teeth  on  a  plate.      The  advisability 

Fig.  502. 


of  extensive  permanently  cemented  bridge-work,  such  as  is  shown 
in  this  and  the  two  cases  preceding  it,  is  very  questionable.     The 


permanency  of  the  latter  probably,  and  most  certainly  that  of  the 
former,  cannot  be  assured. 

The  lateral  force  of  mastication,  exerted  on  the  bridge,  will 


256 


CROWN-,  BRIDGE-.  AND  PORCELAIN-WORK. 


especially  affect  the  side  on  which  the  saddle  is  used,  and  in  time 
is  certain  to  loosen  and  destroy  the  abutments.  Cases  such  as 
these,  where  the  bridge  is  so  extensive  and  the  abutments  so  few, 
are  more  properly  served  by  inserting  what  are  termed  removable 
plate-bridges,  which  have  alveolar  support  in  addition  to  the  abut- 


FiG.  504. 


Fig.  505. 


ments.  The  insertion  of  bridge-work  in  cases  of  this  character  to 
avoid  the  presence  of  a  plate  can  only  be  regarded  as  a  temporary 
expedient  to  afford  a  respite  from  that  annoyance.  It  is  therefore 
a  method  not  to  be  indorsed,  as  the  patient  in  a  short  time  will 


Fig.  506. 


have  to  resort  to  a  plate  and  again  experience  the  initiatory  un- 
pleasantness attending  its  insertion. 

In  the  bridge-work  illustrated  in  Figs.  508,  509,  and  510, 
crowns  on  a  second  bicuspid,  a  pulpless  molar,  and  the  roots  of 
a  cuspid  and  lateral  constitute  the  abutments. 


GENERAL  APPLICATION  OF  CROWN-  AND  BRIDGE-WORK.       257 

Fig.  507. 


Fig.  509. 


258 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Figs.  511  and  512  illustrate  an  extensive  case  of  artificial  re- 
placement by  crowning  and  bridging  operations.  Fig.  511  repre- 
sents the  case  as  presented  for  treatment.  The  few  remaining 
superior  and  inferior  natural  teeth  had  no  corresponding  antago- 


Fig.  510. 


nists,  which  caused  the  interlocking  and  abnormal  condition  in 
regard  to  occlusion  shown.  The  superior  right  bicuspid,  the  left 
central,  and  the  left  cuspid  were  crowned,  the  bicuspid  being  short- 


Fig.  511. 


ened  and  the  cuspid  lengthened  in  the  operation.  The  intervening 
lateral  root  between  the  central  and  cuspid,  having  been  treated 
and  filled,  was  allowed  to  remain.  With  the  three  crowns  to 
serve  as  abutments,  the  intervening  spaces  were  bridged  with  arti- 


GENERAL  APPLICATION  OF  GROWN-  AXD  BRIDGE  WORK.       959 

Fig.  512. 


Fig.  513. 


260 


GROWN-,  BR1DOE-,  AND  PORCELAIN  WORK. 


ficial  teeth,  the  extension  on  the  left  side  being  supported  by  a 
saddle.  The  spaces  between  the  inferior  cuspids  and  molars  on 
both  sides  were  bridged,  the  bicuspid  on  the  left  supporting  the 
bridge,  instead  of  the  cuspid,  as  on  the  right;  the  left  cuspid  was 
crowned  and  the  incisal  edges  of  the  incisors  trimmed  even. 

Fig.  512  illustrates  the  finished  case,  and  shows  the  complete 
artificial  restoration  of  the  parts.1 

Figs.  513  and  514  represent  an  extensive  case  of  crown-  and 
bridge-work.     The  occluding  surfaces  of  the  teeth  were  affected 

Fig.  514. 


with  abrasion.  Gold  crowns  with  porcelain  fronts  which  presented 
laterally  the  form  illustrated  in  Fig.  513  were  mounted  on  the 
incisors  and  cuspids,  the  pulps  of  which  were  preserved.  The 
posterior  teeth  were  crowned  with  all-gold  crowns.  The  missing- 
teeth,  except  those  on  the  lower  left  side,  were  artificially  re- 
stored with  bridge-work. 

Criticism  of.- — Permanently  cemented  bridge-work  of  the  ex- 
tensive stvle  illustrated  in  some  of  these  cases  is  seldom  now  con- 


1  Fifteen  years   after  the  performance   of  these   operations,   this   case  was 
examined  by  the  author,  and  seemed  to  be  in  a  very  fair  condition. 


GENERAL  APPLICATION  OF  CRO^YN-  AND  BRIDGE  WORK.       £61 

structed.  Removable  forms  affording  alveolar  support  are  adopted 
in  preference.  Where  the  abutments  are  numerous  and  offer  suit- 
able supports  to  permit  the  bridge-work  to  be  constructed  in  sec- 
tions around  the  arch,  permanently  cemented  bridges  are  per- 
missible. The  attachment  between  the  sections  of  a  bridge  is 
made  by  anchoring  the  end  of  one  to  the  abutment  of  another 
by  the  use  of  a  spur  anchorage  such  as  is  described  on  pages  223 
and  228,  or  some  one  of  the  devices  in  Chapter  XIII. 


CHAPTER    IX. 

Repair  of  Crown-  or  Bridge-Work. 

the  ordinary  method — dr.  shriver's  method — dr.  w.  w.  william- 
son's method — dr.  starr's  method— dr.  e.  a.  bryant's  method 
— advantages  of  detachable  bridge-work— removal  of 
crowns  or  bridges  cemented  with  zinc  phosphate — re- 
moval of  crowns  or  bridges  cemented  with  gutta-percha- 
repair  of  a  gold  crown. 


FIG.   515. 


The  fracture  of  a  porcelain  front  to  a  permanently  attached 
bridge  is  an  annoying  incident  for  both  patient  and  dentist.  It 
is  usually  attributable  to  failure  to  properly  protect  the  incisal 
edge  or  occlusal  surface  of  the  porcelain  with  metal,  a  precau- 
tion rendered  necessary  by  the  rigid  character  of  the  resistance 
offered  the  antagonizing  teeth  through  the  abutments,  or  by  expo- 
sure of  the  porcelain  in  time  through  loss  of  the  protective  metal 
by  attrition.  In  most  cases  the  porcelain  can  be  replaced  without 
the  removal  of  the  bridge,  but  the  attachment  is  not  usually  so 
reliable  as  in  the  original  piece. 

The  Ordinary  Method. — The  following  is  the  method  com- 
monly adopted  with  incisors  or  cus- 
pids :  The  pins  of  the  broken  fac- 
ing are  cut  off  and  the  surface  of 
the  backing  trimmed  level.  Mark 
the  position  of  the  pins  of  the  new 
facing  on  the  backing  by  drying 
and  flowing  over  the  surface  a  film 
of  beeswax,  then  with  small  pliers 
placing  the  facing  in  position  and 
pressing  the  pins  in  the  wax;  or 
place  a  little  rouge  and  oil  on  the 
end  of  the  pins  and  mark  the  back- 
ing with  them.  At  the  points 
marked  drill  holes  in  the  backing  to  receive  the  pins  of  the  porce- 
262 


REPAIR  OF  CROWN-  OR  HR1DGEW0RK. 


■2Q>3 


Fig.  516. 


lain  front,  countersinking  the  holes  at  the  palatal  side.  After  the 
backing  is  drilled,  grind  the  porcelain  to  fit  it  as  perfectly  as  possi- 
ble, place  it  in  position, 
and  grind  off  the  pins 
so  they  slightly  pro- 
trude. If  a  suitable 
long-pin  tooth  is  not 
procurable,  the  short 
l»in>  of  an  ordinary 
tooth  can  be  length- 
ened by  bending  a 
piece  of  platinum  wire 
in  the  form  of  a  semi- 
circle,    and     soldering; 


&im 


its  end  to  the  ends  of  the  pins  with 
pure  gold.  The  wire  is  then  cut  in 
the  center,  and  the  lengthened  pins 
trimmed  as  required.  The  pins  are 
then  riveted  on  the  palatal  side  into 
the  countersunk  holes  of  the  back- 
ing. The  riveting  is  best  done  with 
punch  forceps  having  a  large 
punch,  the  porcelain  front  being 
protected  by  a  piece  of  lead  place 
against  the  labial  aspect  (Fig.  515). 
The  heads  of  the  pins  should  then 
be  burnished  smooth  with  a  revolv- 
ing burnisher.  In  case  of  the  frac- 
ture of  the  porcelain  front  of  a  bi- 
cuspid crown  or  dummy,  a  corre- 
sponding front  is  selected  with  very 
long  pins,  and  ground  to  fit.    Holes 

are  drilled  in  the  gold,  in  proper  positions,  to  receive  the  pins  their 
full  length.     The  pins  are  then  roughened  a  little  with  a  sharp 


264  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

instrument,  and  pins  and  front  are  cemented  to  the  gold.  Should 
the  holes  extend  through  the  gold  at  the  palatal  side,  the  cement 
and  the  ends  of  the  pins  should  be  covered  with  gold  foil  or  amal- 
gam. If  any  gold  is  present  to  protect  the  occluding  edge  of  the 
porcelain,  it  should  be  burnished  against  the  surface. 

Dr.  Shriver's  Method. — Dr.  F.  M.  Shriver's  method  of  fasten- 
ing the  pins  in  the  backings  of  incisors  and  cuspids  is  as  follows : 
After  having  fitted  the  porcelain  facing  and  shortened  the  pins  as 
described,  remove  the  porcelain  facing  and  with  the  sleeve  drill, 
shown  as  used  in  Fig.  516,  countersink  the  end  of  the  pin;  with 
the  cone  bur — for  right  angle — countersink  the  holes  on  the 
palatal  surface  of  the  backing.  Prepare  a  small  quantity  of  thin 
cement  and  spread  it  over  the  backing,  after  which  place  the  porce- 
lain facing  in  position,  and  with  a  pair  of  pliers  firmly  press  the 
facing  close  to  the  backing.  Warm  a  small  piece  of  modeling 
compound,  place  in  the  cup  on  the  riveting  pliers;  then  set  the 
riveting  point  (see  Fig.  516)  in  the  countersunk  end  of  the  pin, 
gently  pressing  the  facing  into  the  modeling  compound;  remove 
and  cool  compound  with  ice-water.  Replace,  and  with  a  firm  hand 
hold  the  compound  closely  to  the  facing,  and  with  a  gentle  pres- 
sure on  the  riveting  point  and  a  slight  lateral  motion  spread  the 
pin;  then  burnish  it  down  with  the  round  point. 

Dr.  W.  W.  Williamson's  Method. — Another  method  to  replace 
a  porcelain  front  is  the  following :  Back  the  porcelain  front 
around  the  pins  with  platinum  foil,  bend  the  pins  down  together 
on  the  platinum,  and  hammer  them  flat.  Invest  and  flow  a  little 
gold  plate  over  the  pins  and  platinum,  and  file  the  metal  down 
close  to  the  porcelain.  Drill  a  hole  in  a  strong  part  of  the  backing 
on  the  bridge  at  a  central  point,  square  the  hole,  and  fit  to  it  a 
piece  of  square  platinum  wire.  Attach  the  end  of  the  wire  to  the 
backing  of  the  porcelain  front  with  an  atom  of  wax  cement,  and 
while  warm  insert  the  wire  through  the  hole  in  the  backing  on  the 
bridge,  and  adjust  the  porcelain  front  in  correct  position.  Chill, 
and  remove  front  and  wire.  Invest,  and  solder  wire  to  backing  on 
porcelain  front  with  18-carat  gold  solder,  and  then  remove  all 
metal  from  back  of  porcelain,  except  what  is  necessary  to  secure 
the  end  of  the  wire  to  the  pins.  Countersink  the  gold  backing  on 
the  bridge  sufficiently  to  permit  the  front  to  come  in  position.  Slit 
the  end  of  the  wire,  cement  the  porcelain  front  in  position  to  the 
backing,  and  bend  the  ends  outward  into  two  slightly  grooved 


REPAIR  OF  CROWN-  OR  BRIDGE-WORK. 


265 


places  on  the  backing.     Fill  the  slit  in  the  wire  with  gold  or  amal- 
gam, and  smooth  the  surface. 

Dr.  Starr's  Method. — Br.  R  W.  Starr's  method  differs  from 
the  preceding,  in  that  he  uses  round  instead  of  square  wire,  cuts 
the  pins  of  the  porcelain  front  off  short,  making  corresponding 
depressions  in  the  backing  on  the  bridge  to  receive  them  and  pre- 


Fig.  517 


Fig.  518. 


Fig.  519. 


Fig.  520. 


vent  rotation,  and  solders  the  end  of  the  wire  to  retain  the  front 
between  the  pins.  He  then  cuts  a  screw-thread  on  the  wire,  and 
secures  it  in  the  backing  with  a  nut  on  the  palatal  side  screwed 
into  a  depression  reamed  to  receive  it.  Figs.  517,  518,  519,  and 
520  illustrate  this  method. 

Dr.  Bryant's  Method. — Dr.  E.  A.  Bryant  describes  a  method1 
of  repairing  bridge-work  by  the  aid  of  a  set  of  tools,  now  made  and 


Fig.  521. 


■  ■UUxU^lu^^ 


sold  for  the  purpose,  which  easily  accomplishes  the  results  ob- 
tained in  the  preceding  example.  Dr.  Bryant's  method  and  tools 
are  briefly  described  as  follows :  Each  pin  of  the  selected  tooth- 
facing  is  to  be  screw-threaded,  first  oiling  the  pin,  starting  with  die 
No.  1,  Eig.  521,  and  finishing  with  die  Xo.  2.     The  pin-holes  in 


1  Dental  Cosmos,  June.  1894.  page  370. 


2G6  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

the  bridge  backing  are  countersunk  from  the  rear  with  the  right- 
angle  engine  reamer  No.  3.  (See  A.)  With  the  nut-driver  No.  4 
or  4  A  (No.  4  for  hand  manipulation,  No.  4  A  for  engine  work), 
one  of  the  gold  nuts  No.  5  is  caught  on  one  prong  (see  B),  and 
started  on  one  of  the  pins  (see  C),  and  then  the  other  nut  is  like- 
wise started.  Turning  one  after  the  other,  the  nuts  are  screwed 
tightly  on  (see  D),  and  then  with  engine-points  the  projecting 
pins  and  nuts  are  ground  flush  with  the  backing. 

Advantages  of  Detachable  Bridge=Work. — If  the  character  of 
the  breakage  will  not  permit  repair  in  the  mouth,  the  bridge  must 
be  removed  and  reinserted.  Under  such  circumstances  the  ad- 
vantages of  a  detachable  form  are  evident. 

Bridge-work  can  be  made  with  replaceable  porcelain  fronts 
which  can  be  easily  substituted  in  case  of  fracture.  A  description 
of  their  application  will  be  found  at  page  239. 

The  additional  time  required  to  render  some  cases  of  bridge- 
work  suitable  for  cementation  with  gutta-percha  cement  is  trifling 
compared  to  that  which  would  be  consumed  in  the  construction 
of  the  same  work  with  replaceable  porcelain  facings. 

The  results  following  the  repair  of  single  crowns  in  the  mouth 
will  seldom  repay  the  labor  attending  it- 
Removal  of  Crowns  or  Bridges  Cemented  with  Zinc  Oxy=- 
phosphate. — When  it  becomes  necessary  to  remove  an  artificial 
crown,  whether  inserted  singly  or  as  a  support  for  a  bridge,  in- 
cisors or  cuspids  are  detached  by  grinding  the  gold  or  porcelain 
away  at  the  palatal  section  over  the  post,  which  when  exposed  is 
severed,  and  the  attachment  of  the  cement  broken  up.  The  collar 
can  also  be  slit  and  bent  aside  if  found  necessary.  If  previous  to 
cementation  the  post  of  the  crown  is  covered  with  a  film  or  sheath 
of  gutta-percha,  as  described  in  the  process  of  cementation  on  page 
165,  the  detachment  of  the  post  is  usually  effected  easily.  In  an  all- 
gold  cap-crown  on  a  posterior  tooth  a  hole  drilled  in  the  grinding- 
surface  will  give  access  to  the  cement,  a  sufficient  quantity  of 
which  can  then  be  removed  to  loosen  the  attachment;  or,  the  collar 
can  be  divided  and  pried  up  from  the  root  by  first  making  a  groove 
with  a  small  rubber  and  corundum-disk,  and  then  cutting  the  gold 
with  a  sharp  instrument.  A  crown-slitter,  an  instrument  made  for 
the  purpose,  will  facilitate  this  part  of  the  operation.  (See  Fig. 
522.)  With  care  and  patience  in  the  operation,  the  crowns  will 
not  usually  be  injured  beyond  repair. 


REPAIR  OF  CROWN-  OR  BRIDGE-WORK.  267 

Removal  of  Crowns  or  Bridges  Cemented  with  Qutta= 
Percha. — In  cases  of  metallic  collar  or  cap-crowns,  first  slightly 
raise  the  edge  of  the  collar,  especially  if  burnished  over  a  project- 
ing point.  Protect  the  membranes  and  spread  a  napkin  across  the 
mouth  over  the  lower  lip.  Heat  a  crown-heater  almost  to  a  red  heat. 
Place  your  finger  against  the  artificial  crown  and  apply  the  crown- 
heater.  For  bicuspids  and  molar-,  apply  the  crown-heater  to  the 
occlusal  surface,  and  for  incisors  and  cuspids,  at  the  palatal  side 
toward  the  incisal  edge.  As  the  crown  receives  the  heat,  it  is  indi- 
cated to  your  finger.  When  the  heat  is  raised  to  a  point  as  high 
as  your  finger  can  comfortably  bear,  the  crown-heater  should  be 
removed  for  an  instant  until  the  crown  slightly  cools,  then  it 
should  be  applied  again.  In  heating  a  crown  it  is  well  to  notify 
the  patient  to  raise  the  left  hand,  should  the  heat  at  any  time 
become  painful.  The  application  of  the  heat  must  be  continued 
as  directed  for  at  least  three  minutes  until  the  cement  is  thoroughly 

Fig.  522. 


softened,  which  proceeds  slowly,  owing  to  its  contact  with  the 
natural  crown  or  root.  In  a  case  of  bridge-v^ork,  as  soon  as  one 
crown  is  heated,  instantly  pass  the  crown-heater  along  the  surface 
of  the  bridge,  to  other  crown  or  crowns,  and  then  back  and  forth, 
until  all  the  attachments  are  uniformly  heated.  When  this  has 
been  effected,  start  the  bridge  at  one  end  and  then  at  the  other,  or 
at  both  together,  and  lift  it  from  position. 

Repair  of  a  Gold  Crown. — A  hole  or  slit  in  a  gold  collar  or 
crown  is  repaired  easily  by  first  placing  a  piece  of  soft  wax  in  the 
hole  or  slit  on  the  outside  of  the  gold,  adapting  a  piece  of  platinum 
foil  larger  than  the  aperture  on  the  inside  close  against  the  gold, 
and  attaching  it  to  the  wax.  The  interior  of  the  crown  is  next 
filled  with  investing  material,  and  solder  flowed  over  the  platinum 
and  srold  on  the  outside  of  the  collar  or  crown.  The  crown  should 
be  heated  slowly,  to  allow  the  plaster  to  dry  out  before  the  solder- 
ing is  begun. 

to 


CHAPTER    X. 

The  Hygienic  Condition  of  the  Mouth  as  Affected  by 
Bridge-Work. 

consideration    of    the    subject — requirements — methods    for 
cleanliness  and  health. 

Consideration  of  the  Subject. — The  probable  future  condition 
of  a  mouth  in  which  a  piece  of  bridge-work  is  permanently  fixed 
is  a  matter  of  the  deepest  interest  to  both  patient  and  operator. 
There  is  no  valid  reason  why  an  artificial  structure  in  the  mouth 
should  be  more  hurtful  than  that  which  is  natural,  provided  that 
correct  conditions  are  observed  in  its  construction  and  proper 
measures  are  taken  for  their  maintenance.  The  natural  teeth  de- 
mand care  on  the  part  of  their  owners,  and  all  forms  of  artificial 
dentures  require  attention  to  secure  their  cleanliness  and  thus 
preserve  the  health  of  the  adjacent  tissues.  What  will  result  from 
the  wearing  of  a  permanently  fixed  bridge  is  almost  wholly  de- 
pendent, in  the  first  place,  on  the  proper  application  of  principles 
and  correct  formation  in  every  detail  of  construction  of  both 
crowns  and  bridge-work;  and  in  the  second  place,  upon  the  mainte- 
nance of  cleanliness.  Neglect  of  a  single  requirement  will  so  far 
detract  from  the  usefulness  of  the  work,  and  may  influence  the 
final  result  disastrously. 

Requirements. — Firm,  properly  selected  abutments  will  not  re- 
deem incorrect  conception  or  faulty  construction;  neither  will  the 
best  construction  remedy  that  which  is  wrong  in  principle  or  appli- 
cation. Self -cleansing  spaces,  if  improperly  formed,  have  exactly 
the  contrary  effect  from  what  is  intended,  by  becoming  recep- 
tacles for  particles  of  food  debris,  instead  of  preventing  their  ac- 
cumulation. 

Inaccessible  spaces  or  interstices,  which  are  always  apt  to  cause 
uncleanliness,  should  be  avoided.  Continuity  of  structure  of  the 
several  parts  is  also  essential  to  fully  insure  perfect  hygienic  condi- 
tions. 

268 


HYGIENIC  CONDITIO X  AS  AFFECTED  BY  BRIDGE-WORK.        269 

Methods  for  Cleanliness  and  Health. — The  health  of  a  mouth 
containing  a  piece  of  bridge-work  constructed  under  these  precau- 
tions can  be  readily  maintained.  For  this  purpose  a  suitably 
formed  tooth-brush  and  properly  shaped  bristle  points  in  a  carrier 
which  will  reach  places  not  cleaned  by  the  brush  with  a  dentifrice 
are  necessary.  Floss  silk  can  be  passed  through  apertures  around 
the  necks  of  crowns  by  the  aid  of  a  slightly  curved  blunt-pointed 
needle  and  drawn  along  the  gum  under  the  bridge  to  remove  ac- 
cumulations of  debris  otherwise  inaccessible.  A  solution  of  a 
detergent  and  disinfectant  mouth-lotion  in  water,  injected  with  a 
dental  syringe,  can  be  used  advantageously  to  wash  out  such  places 
and  maintain  a  healthy  condition  of  the  gums.  In  addition  to 
these  measures,  the  crown  and  bridge  should  be  thoroughly 
cleansed  by  the  dentist  at  regular  intervals. 

So  cared  for,  a  permanently  fixed  bridge  will  not  militate  against 
the  absolute  wholesomeness  of  the  mouth;  but  it  can  hardly  be 
expected  that  the  insertion  of  bridge-work  will  insure  a  state  of  the 
mouth  which  for  cleanliness  will  be  superior  to  the  presence  of  the 
natural  teeth.  Xeglect  on  the  part  of  the  patient  to  perform  such 
duties  as  are  necessary  to  preserve  the  natural  teeth  in  a  healthy 
state  will  have  about  the  same  effect  on  an  artificial  denture.  The 
attention  required  to  be  given  to  bridge-work  is  not  greater  than 
is  commensurate  with  the  advantages  which  it  confers  on  the 
wearer. 


CHAPTER    XL 

Removable  and  Detachable  Bridge-Work. 


LIMITATIONS— REQUIREMENTS— REMOVABLE  INCISOR  OR  CUSPID  CROWN 
—SPLIT  OR  SPRING  POST— THE  TUBE— UNION  OF  TUBE  AND  CAP- 
TAPERING  SPRING  POST— CROWN-POST,  DETACHABLE  OR  REMOV- 
ABLE CROWN— REMOVABLE  BICUSPID  AND  MOLAR  ATTACHMENTS- 
REMOVABLE  COLLAR  AND  PARTIAL  CAP— FLANGED  COLLAR  AT- 
TACHMENT—SPUR COLLAR  SUPPORT— REMOVABLE  CLASP  AND  PAR- 
TIAL CAP  ATTACHMENT  :  CUSPIDS  :  BICUSPIDS— CONNECTING  BARS— 
FOR  THE  UPPER  FRONT  TEETH— CONSTRUCTION  OF  REMOVABLE 
BRIDGE-WORK. 

The  evident  advantages  of  bridge-work  early  stimulated  the 
inventive  genius  of  dental  mechanists  to  improve  the  methods 
and  forms  of  its  construction  and  to  extend  its  application.  With 
these  objects  in  view,  methods  have  been  introduced  by  which 
bridges  are  so  constructed  as  to  be  removable  by  the  patient  or  de- 
tachable by  the  dentist.  The  construction  of  bridge-work  in  either 
of  these  forms  in  some  cases  overcomes  the  chief  objections  urged 
against  the  system. 

Large  bridges  are  much  more  easily  made  in  a  detachable  or 
removable  form  than  are  the  smaller  pieces,  which  present  some  of 
the  best  features  of  the  permanently  attached  methods. 

Limitations — Some  forms  of  small  bridges  cannot  be  made 
removable.  To  so  construct  many  others  would  interfere  with 
their  practicability.  Besides,  in  a  large  proportion  of  cases  where 
properly  constructed  bridge-work  is  applied,  the  removable  feature 
would  be  of  no  benefit,  so  far  as  regards  the  health  of  the  abut- 
ments or  of  the  adjoining  teeth;  neither  would  it  be  of  any  great 
advantage  respecting  cleanliness.  These  reasons,  together  with 
the  fact  that  removable  bridge-work  is  most  intricate  and  laborious 
in  construction,  combine  to  restrict  its  use  in  practice  to  the  form 
270 


A'/:  l/o  l    1/;/./:  AND  DETACHABLE  BRIDGE-WORK.  271 

termed  removable  plate  bridge-work.  Much  that  is  here  stated 
concerning  removable  bridge-work  might  be  applied  to  the  de- 
tachable form.  The  necessity,  on  the  part  of  the  dentist,  for  using 
the  latter  in  preference  to  the  former  is  limited  to  a  very  small 
sphere  owing  to  the  fact  that  gutta-percha,  alone  or  combined 
with  oxyphosphate,  can  be  used  practically  a-  a  cement  in  most 
cases,  thus  at  any  time  permitting  the  removal  of  a  bridge  without 
much  difficulty. 

Requirements. — In  the  construction  of  removable  bridge-work 
a  prime  requisite  is  that  the  posts  and  collars,  or  other  form  of 
attachment  used,  shall  be  so  formed  that  the  piece  shall  move 
evenly  on  or  off  the  supporting  roots  or  crowns  in  adjustment  and 
removal.  To  secure  this,  the  post-cavities  and  the  gold  ctoavih 
should  be  so  shaped  that  the  lines  of  the  cavities  and  of  the  sides 
of  the  gold  crowns  shall  be  as  nearly  as  possible  parallel  to  one 
another.  To  facilitate  this,  a  post  of  wood  or  metal  may  be  first 
accurately  but  loosely  inserted  in  any  root-canal  intended  to  re- 
ceive a  post;  and  left  protruding  a  quarter  of  an  inch,  and  an  im- 
pression taken.  On  the  model  made  from  this  impression  the  post 
will  be  found  placed  as  in  the  mouth.  The  position  and  shape  of 
the  natural  teeth  or  roots  can  be  thus  studied,  and  their  plaster 
forms  trimmed  as  a  guide.  Gutta-percha  or  impression-compound, 
fitted  to  the  model  and  removed  with  the  posts  in  position  in  it, 
can  then  be  used  to  guide  the  operator  and  gage  the  preparation  of 
teeth  or  roots  in  the  mouth.  Posts,  or  the  tubes  inclosing  them, 
should  be  placed  as  nearly  as  possible  in  the  lines  of  the  root-canal.- 
to  avoid  weakening  the  side  or  sides  of  the  root. 

When  a  molar  leans  forward,  the  removal  of  a  portion  of  the 
mesial  side  usually  restores  its  perpendicularity  sufficiently,  as  does 
the  cutting  away  of  the  distal  side  of  a  bicuspid  which  inclines 
backward. 

The  methods  and  forms  of  attachments  most  commonly  used 
in  the  different  styles  of  removable  bridge  dentures  are  in  principle 
very  similar.  A  preliminary  description  of  these  and  of  their  con- 
structive details  is  therefore  first  in  order. 

Removable  Incisor  or  Cuspid  Crown. — A  removable  gold 
crown  with  a  porcelain  front  is  frequently  used  in  connection  with 
removable  bridge-work  where  incisors  or  cuspids  form  abutments. 
The  cap  and  tube  crown  is  the  style  (Fig.  523)  preferably  applied. 


7 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


It  consists  of  a  cap  for  the  end  of  the  root  with  a  tube  attached 
extending  up  the  root-canal,  and  on  the  cap  the  crown  with  a  post 
fitted  tightly  to  the  tube  is  adjusted.  To 
the    crown    so    formed    (Fig.     524)    the 


Fig. 


bridge  is  joined  in  the  usual  manner.  The 
end  of  the  post  can'  be  formed  with  a  slit 
which  will  permit  this  portion  to  be  slightly- 
expanded,  making  what  is  termed  a  spring- 
post.  The  constructive  details  of  this 
crown  are  as  follows :  The  root  is  first 
prepared  and  capped  the  same  as  for  a 
collar  crown.  The  collar  can  be  formed  of 
gold  and  the  cap  section  of  platinum.  Xo. 
32  gage  I  A.  Fig.  r>25). 

Split  or  Spring=Post. — A  substantial 
of  gold  and  platinum  wire,  from  Xo. 
10  to  X".  Is  gage  (the  number  being  regulated  by  the  size  of  the 
root),  is  slit  fur  about  one-eighth  of  an  inch  to  form  a  spring-post. 
This  is  easily  done  by  placing  the  wire  in  a  vise  and  steadily 
cutting  it  downward  from  one  end  through  the  center  to  the  re- 
quired depth  with  a  saw-edged  strip  of  very  thin  steel  (Fig.  526). 
This  takes  only  a  few  minutes,  and  is  preferable  to  the  method 
sometimes  adopted  of  partially  joining  two  pieces  of  half-round 
wire. 

The  wire  is  then  tapped  together  at  the  slit,  burnished  smooth, 
and  rounded  just  at  the  end  (B,  Fig.  525). 

The  Tube — The  tube  for  this  post  is  formed  by  once  encircling 
the  post  with  a  piece  of  iridio-platinum  plate,  Xo.  3-i  gage,  the 
edge  of  which  is  beveled  and  cut  to  meet  the  plate  even  and 
close  (C).  The  post  is  then  withdrawn,  and  the  seam  is  touched 
along  its  length  with  the  smallest  possible  quantity  of  borax.  The 
proper  way  to  use  borax  in  fine  work  is  to  grind  it,  mixed  with 
water,  on  a  slab,  to  a  cream-like  consistence,  and  apply  with  the 
point  of  a  cameTs-hair  brush.  A  very  small  piece  of  pure  gold  is 
placed  in  the  seam,  and  the  tube  is  held  in  a  Bunsen  flame.  "When 
a  sufficient  degree  of  heat  is  reached,  the  gold  will  flow  along  the 
seam  and  form  a  joint  without  obstructing  the  inside  passage  for 
the  post.  The  post  is  then  inserted,  and  the  tube  trimmed  CD), 
and  gaged  in  a  gage-plate.  With  a  drill  just  the  size  of  the  tube 
the  root-canal  is  enlarged  so  that  the  tube  will  fit  tightly  (Fig. 


REMOVABLE  AND  DETACHABLE  BUWGEAYORK. 


273 


527).      This  plan  prevents  weakening  of  the  root  by  too  great 
enlargement  of  the  canal. 

Union  of  Tube  and  Cap. — A  hole  the  size  of  the  tube  is  made 
through  the  cap,  and  cap  and  tube  are  then  adjusted,  waxed  to- 
gether, and,  the  post  being  withdrawn,  they  are  removed,  invested, 
with  the  investing  material  inserted  in  the  tube,  and  soldered. 
The  second  or  outer  cap  is  then  constructed  for  the  root-cap,  of 
platinum  about  Xo.  34  gage.  It  is  perforated  in  the  center,  and 
the  post  fitted  in  proper  position.  At  the  palatal  and  approximal 
sides,  if  desirable,  the  platinum  can  be  slit  and  bent  over  the  edge 
of  the  root-cap  to  form  an  inner  partial  band  or  flange,  or  a  half 
band  can  be  formed  of  a  piece  of  plate,  the  open  space  at  the  labial 
side  being  filled  with  the  porcelain  tooth.     The  outer  cap  and  the 


Fig.  526. 


Fig.  527. 


post  are  cemented  with  wax.  removed,  invested  and  soldered 
ther.  As  the  point  of  the  post  may  have  to  be  filed,  it  is  well  to 
place  it  so  that  the  line  of  the  slit  shall  cross  the  tooth  from 
mesial  to  distal  side.  On  this  outer  cap  the  porcelain  front  is 
fitted  and  soldered.  The  end  of  the  tube  is  closed  with  a  little 
gutta-percha,  and  the  root-cap  cemented  on  the  root  with  oxy- 
phosphate  and  the  crown  placed  on  it,  which  helps  to  bring  the 
root-cap  to  its  place  and  insures  the  intended  position  of  the 
crown.  When  necessary,  the  split  post  can  be  tightened  in  the 
tube  by  slightly  springing  it  open.  Fig.  524  represents  the  fin- 
ished crown.  The  incisal  edge  of  the  porcelain  does  not  neces- 
sarily require  to  be  protected  with  metal  as  in  fixed  bridge-work. 
Tapering  Spring=Post. — A  tapering  or  square  post,  either  solid 
or  split  in  some  cases,  is  preferred  to  the  form  above  described, 
especially  in  the  root  of  a  cuspid.  When  a  tapering  split  post 
is  used,  the  points  should  be  soldered  together.     The  lower  sec- 


274 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  528. 


Fig.  529. 


tion  of  the  post  can  then  be  alone  expanded  and  tightened 
in  the  tube  (Fig.  528).  To  receive  this  style  tube  and  post, 
the  canal  should  be  deeply  opened  with  care  and  then 
shaped  with  a  reamer,  such  as  is  illustrated  at  Fig. 
96. 

Crown=Post,  Detachable  or  Removable  Crown. — 
A  cap  for  the  end  of  the  root  with  a  root-post  (Fig.  529, 
in  section)  is  first  made  and  a  porcelain  front  fitted  and 
attached  with  wax.     Plaster  is  applied  to  the  cap  and 
labial  surface  of  the  front  to  form  a  matrix  and  the  wax 
removed.     An  iridio-platinum  post,  about  No.   15  to 
16  gage,  incased  with  a  tube  of  platinum  foil,  is  fitted 
in  position  back  of  the  front  on  the  cap  between  the 
pins,  if  possible  without  removing  any  of  the  porcelain 
between  them.     The  end  of  the  post  is  cemented  with 
wax  to  the  cap,  the  platinum  foil  post  removed,   and  cap  and 
post  invested  and  securely  joined  with  solder.     A  disk  of  plati- 
num foil  is  next  perforated  and  adapted  to  the  cap.     The  tube 
is  again  fitted  on  the  post,  the  front  lined  with  plati- 
num foil,  placed  in  position,  and  attached  with  wax 
to  tube  and  disk,  removed,  invested,  and  soldered. 
This  forms  a  crown  for  the  root-cap  which  can  be 
used  to  support  one  end  of  a  detachable  or  removable 
bridge  if  the  other  end  is  more  securely  held  by  a 
bicuspid  or  molar  crown. 

Removable  Bicuspid  and  Molar  Attachments. 
— Bicuspids  and  molars,  especially  the  latter,  in  all 
cases  where  possible,  are  the  teeth  selected  and  most  depended 
on  to  support  all  forms  of  removable  bridge-work. 

Removable  Collar  and  Partial  Cap. — This  is  a  form  of  attach 
ment  made  to  fit  over  a  natural  tooth,  or  more  frequently  a  gold 
crown. 

The  sides  of  the  natural  tooth  are  to  be  first  trimmed  as  nearly 
as  possible  straight  and  parallel  to  the  sides  of  any  other  supporting 
crown  or  line  of  attachment.  If  the  tooth  is  to  be  first  capped,  a 
straight-sided  gold  crown  is  made  and  fitted.  A  fusible-metal  die 
of  the  gold  crown  is  then  made;  or,  better  still,  the  gold  crown  is 
removed,  a  strip  of  damp  paper  wound  around  it,  and  fusible 
metal  melted  and  poured  in  crown  and  paper  tube.  This  forms  a 
die  of  the  crown,  with  a  shank  as  seen  in  Fig.  530.     When  the 


REMOVABLE  AND  DETACHABLE  BRIDGE-WORK.  275 

natural  tooth  is  not  crowned  with  gold,  a  die  of  the  tooth  is  made 
in  a  manner  similar  to  that  described  in  Part  Y.  (  lhapter  III.  and 
in  Part  II,  Chapter  VIII.  The  crown  is  then  encircled  with 
a  strip  of  pure  gold,  about  No.  30  gage,  one  part  of  which,  B,  will 
extend  above  the  rest  in  the  form  shown  in  Fig.  531. 

The  sections  of  the  gold  at  A  A  are  to  reach  from  the  edge 
of  the  neck  of  the  crown  to  or  slightly  above  the  occluding  sur- 
face. The  gold  is  fitted  evenly,  but  not  tightly,  around  the  crown, 
the  ends  being  placed  at  the  side  opposite  to  that  where  the  collar 
will  be  joined  to  the  bridge  if  the  space  permits.  The  collar  is 
then  removed  and  the  ends  soldered  together  (Fig.  532).  The 
collar  is  readjusted  on  the  crown,  and  the  part  at  B,  Figs.  532  and 
53  1.  bent  down  over  the  occluding  surface,  so  that  it  nearly  meets 
the  collar  section  A.  On  the  outside  of  the  collar  a  slightly  nar- 
rower strip  of  gold  clasp-plate.   No.   30  gage  (Fig.  533),  is  next 


Fig.  530. 


Fig.  531. 


X~^~L 


adjusted  in  the  position  shown  at  the  lines  C,  Fig.  534,  then 
removed,  and  the  seam,  which  had  best  be  located  at  the  point  C, 
Figs.  533  and  534,  soldered  together.  It  is  readjusted  on  the 
gold  collar,  removed  with  it,  and  soldered  to  it.  The  collar  can 
be  invested  for  this  purpose,  but  the  work  is  more  easily  done  by 
holding  it  in  a  Bunsen  flame  and  placing  small  pieces  of  solder  in 
position  in  the  seam.  Only  enough  solder  should  be  used  to  unite 
the  parts,  any  surplus  being  carefully  avoided.  Painting  the 
inner  surface  of  the  collar  with  whiting,  or  the  use  of  dampened 
marble-dust,  will  prevent  the  solder  flowing  there. 

The  collar  section  of  the  removable  cap  is  then  trimmed  smooth. 
The  flap  section  at  B  can  be  adapted  to  the  occluding  surface  of 
the  gold  crown  now  and  reinforced  with  solder,  or  preferably 
after  the  collar  section  has  been  united  to  the  bridge,  and  its  rel- 
ative position  on  the  gold  crown  when  cemented  in  the  mouth 


276  CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 

accurately  determined.  Fig.  535  shows  the  gold  crown  and  the 
finished  removable  partial  gold  cap  over  it. 

The  gold  crown  is  freed  from  the  fusible  metal  by  dropping 
it  with  the  die  into  a  ladle  containing  a  quantity  of  melted  fusible 
metal.  The  portion  within  the  crown  will  melt  in  with  that  in 
the  ladle  and  leave  the  crown,  which  should  then  be  removed 
and  immersed  in  nitric  acid  to  remove  any  traces  of  the  fusible 
metal  still  adhering  to  the  gold.  If  the  fusible  metal  will  melt 
below  200°,  boiling  water  will  remove  it. 

Flanged  Collar  Attachment — Fig.  536  shows  another  form 
of  removable  partial  cap.  In  this  the  entire  edge  of  the  collar  is 
bent  over  on  the  occluding  surface  of  the  crown,  and  thereby 
supported  in  position.  In  the  construction  the  edge  of  the  pur-' 
gold  collar  should  be  shaped  to  form  the  flange. 

Fig.  533.  Fig.  534.  Fig.  535.  Fig.  536. 


This  form  of  collar  may  also  be  made  entirely  of  clasp-gold, 
]STo.  28  gage  for  molars,  and  of  Xo.  29  to  30  gage  for  bicuspids. 
The  process  is :  An  accurately  fitting  collar  is  first  made.  The 
collar  is  then,  by  tapping  with  a  small  horn  or  copper  hammer, 
aided  by  frequent  annealings,  shaped  on  the  gold  crown  or  die 
of  the  tooth.  The  flange  section  can  be  slightly  thinned  with 
a  small  corundum-wheel,  and  then  or  subsequently  brought  to 
position  over  the  gold  crown,  or  the  tooth,  and  stiffened  with 
solder.  When  the  collar  is  shaped  over  the  gold  crown,  the 
crown  should  be  first  filled  with  fusible  metal  as  previously  de- 
scribed. 

Spur  Collar  Support — Fig.  537  illustrates  a  form  in  which  a 
straight-sided  removable  collar  is  maintained  in  position  by  a 
lug  or  spur  on  the  side  of  a  gold  crown. 

Removable  Clasp  and  Partial  Cap  Attachment  :  Cuspids. — 
In  this  form  a  partial  cap  in  combination  with  an  elastic  gold 
clasp,  encircling  only  a  portion  of  the  crown,  is  used  instead  of  a 


REMOVABLE  AND  DETACHABLE  BRIDGE-WORK. 


277 


collar.    Its  application  is  principally  confined  to  a  cuspid  or  bicus- 
pid tooth  or  an  artificial  crown. 

The  attachment  is  best  constructed  on  a  metallic  die,  either 
of  the  natural  tooth  or  of  the  artificial  crown  mounted  on  a  model. 
In  the  case  of  a  cuspid  a  piece  of  pure  gold,  ]STo.  31  gage,  is 
adapted  to  the  palatal  surface  and  partly  over  on  the  approximal 
side,  in  the  form  shown  at  A,  Fig.  538.  In  some  cases  it  may  be 
extended  to  the  incisal  edge.  A  gold  clasp  of  at  least  No.  24 
gage  is  fitted  over  the  gold  partial  cap  in  the  position  shown  in 
Fig.  539,  the  cap  being  beveled  to  an  imperceptible  edge  on  the 
sides  at  the  points  where  the  clasp  passes  forward,  to  assure  perfect 
adaptation.  Cap  and  clasp  are  next  cemented  with  wax,  then  re- 
moved and  joined  at  the  approximal  sides  with  a  very  small  quan- 
tity of  solder.     The  attachment  is  then  ready  to  be  connected  to 


Fig.  537. 


Fig.  538. 


Fig.  539. 


Fig.  540. 


the  bridge  denture,  which  should  be  done  by  soldering  the  clasp 
portion  only  at  the  point  B,  Fig.  539.  This  method  allows  the 
soft  gold  of  the  cap  portion  to  be  again  adapted  to  suit  any  posi- 
tion the  clasp  may  assume  in  a  later  adjustment  of  the  denture 
in  the  mouth.  AVhen  this  has  been  done,  the  bridge  and  clasp 
should  be  again  invested,  and  solder  flowed  over  and  between  the 
cap  and  clasp. 

Bicuspids. — Fig.  540  illustrates  the  form  the  attachment  just 
described  usually  assumes  in  cases  of  bicuspids.  The  dotted  line 
marks  the  boundary  of  the  partial  pure  gold  cap.  The  construc- 
tion follows  similar  lines  to  those  laid  down  in  the  case  of  a  cuspid. 
If  preferable,  the  cap  section  can  be  burnished  down  against  the 
crown:  and,  if  necessary,  it  can  be  slit,  and  solder  can  be  flowed 
over  it  at  the  final  adjustment  of  the  bridge.  This  form  of  at- 
tachment is  especially  useful  in  cases  where  a  natural  tooth  tips 
out  of  line  so  as  to  render  it  difficult  to  entirely  encircle  it  with  a 


278  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

continuous  band.  Such  an  attachment  is  seldom  applied  to  a 
molar. 

Pure  gold  has  been  given  the  preference  to  thin  platinum  in 
the  construction  of  these  partial  caps,  for  the  reason  that  the 
form  and  the  position  of  the  gold  are  less  liable  to  be  altered 
in  soldering,  an  advantage  which  is  relatively  more  important 
than  the  non-fusible  quality  of  the  platinum. 

The  forms  of  attachments  described  for  removable  bridge- 
work  are  those  most  generally  applied  in  practice.  The  methods 
for  their  construction,  which,  as  given,  are  the  results  of  practical 
experience,  may  in  some  respects  differ  from  those  followed  by 
others.  In  application,  as  will  be  shown,  they  enable  the  operator, 
by  the  methods  of  their  construction,  to  overcome  difficulties  often 
encountered  in  obtaining  a  proper  adjustment  of  removable 
bridges  on  the  abutments  and  alveolar  border.  Special  forms  of 
attachments  not  in  general  use  will  be  described  in  the  succeeding 
chapters,  in  their  application  to  practical  cases.  Their  use  in  com- 
bination with  the  forms  already  explained  may  at  times  prove 
advantageous. 

Connecting  Bars. — Connections  between  the  different  sections 
of  a  removable  bridge  are  formed  in  the  following  manner :  An 
impression  of  the  case  or  of  the  part  to  be  spanned  is  taken  in 
plaster,  and  a  cast  made  by  pouring  into  it  fusible  metal  which 
melts  at  a  point  less  than  or  not  over  200°.  The  cast  must  cor- 
rectly represent  the  lingual  or  palatal  surfaces  of  the  teeth.  Upon 
this  cast  a  strip  of  pure  gold,  JSTo.  30  gage,  about  one-quarter  of  an 
inch  in  width  and  of  the  proper  length  for  the  required  connecting 
bar,  is  burnished  over  the  palatal  or  lingual  surface  of  the  teeth 
intervening  between  sections  of  the  bridge  or  attachments  to  be 
connected.  Wax  is  placed  on  the  gold,  and  the  gold  removed  and 
invested.  The  wax  is  next  removed,  and  pieces  of  gold  clasp- 
plate  a  trifle  narrower  t  li;1  u  the  s1  rip  of  pure  gold,  one  to  each  tooth, 
are  bent  and  shaped  to  fit  over  the  lingual  surface  of  each. 
Twenty-carat  solder  is  then  flowed  over  the  gold  in  quantity  suf- 
ficient to  join  the  parts,  level  the  surface,  and  make  a  rigid  bar 
capable  of  resisting  such  force  in  use  as  would  tend  to  destroy  its 
shape  in  the  slightest  degree.  When  the  bar  is  formed  on  the 
metallic  cast  it  can  be  transferred  to  the  plaster  model,  and  then, 
or  in  the  subsequent  construction  of  the  work,  connected  to  the 
attachments;  or  the  bar  can  be  adjusted  in  the  mouth,  cemented 


REMOVABLE  AXD  DETACHABLE  BRIDGE-WORK.  279 

with  wax  or  ligatured  on  the  teeth,  the  attachments  placed  in  posi- 
tion, and  the  bar  and  attachments  removed  in  their  relative  posi- 
tions in  a  plaster  impression.  On  the  model  made  from  this 
impression  they  will  be  found  the  same  as  in  the  mouth.  The 
construction  of  the  bridge  can  then  be  continued.  Fig.  541  repre- 
sents a  bar  of  this  character  to  span  the  lower  front  teeth  and 
connect  attachments  on  the  cuspid  and  bicuspid. 

For  the  Upper  Front  Teeth. — Where  a  bar  narrower  than  the 
one  described  is  required,  the  strip  of  pure  gold  should  be  cut  pro- 
portionately, and  pieces,  one  to  each  tooth,  of  half-round  iridio- 
platinum  or  gold  clasp-wire  used  to  form  and  stiffen  the  bar, 
instead  of  gold  clasp-plate.  Iridio-platinum  wire  may  be  used 
without  the  pure  gold  base,  but  in  such  a  case  the  sections  of  the 
wire  are  best  soldered  with  either  pure  gold  or  22-carat  plate. 


Methods  for  connecting  sections  of  a  bridge  are  illustrated  in  Figs. 
390,  470,  472,  474,  54G,  550,  560,  648,  and  652. 

Construction  of  Removable  Bridge=Work. — In  removable,  as 
well  as  other  styles  of  bridge-work,  the  method  of  procedure  is 
governed  entirely  by  the  conditions  presented  in  each  case. 
Therefore  directions  given  regarding  bridge-work  embracing  cer- 
tain teeth  and  attachments  in  one  instance  may  vary  considerably 
from  what  is  required  for  the  same  tooth  in  another;  consequently 
the  process  of  construction  can  only  be  outlined  in  somewhat  gen- 
eral terms. 

A  case  frequently  presented,  involving  the  loss  of  a  portion  of 
the  lower  teeth,  as  shown  in  Fig.  542,  will  be  taken  to  illustrate 
the  method  generally  adopted  for  the  construction  of  removable 
bridge-work. 


280 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


The  molar  is  shaped  to  receive  a  gold  crown.  The  anterior 
approximal  side  is  trimmed  parallel  with  the  line  of  the  posterior 
side  of  the  cuspid.  Removing  a  little  of  the  enamel  on  the  distal 
side  of  the  cuspid  will  assist  the  operation  and  straighten  that 
part  of  the  tooth.  A  straight-sided  gold  crown  is  made  for  the 
molar.  A  bite  is  first  taken  in  wax  for  articulating  model  and 
then  a  plaster  impression,  which  will  remove  the  gold  molar  crown 
in  position,  and  a  cast  is  made  as  follows :  The  form  of  the  cuspid 
and  the  gold  crown  are  first  filled  with  fusible  metal,  and  the  re- 
mainder of  the  impression  with  pure  plaster,  as  described  in  Part 
V,  Chapter  III. 

A  die  is  then  made  of  the  gold  crown  and  a  removable  cap  for 
the  gold  crown  on  this  die,  and  a  gold  partial  cap  and  clasp  attach- 
ment are  made  on  the  metallic  form  of  the  cuspid.  If  the  condi- 
tions suggest  it,  the  gold  band  should  be  made  to  entirely  encircle 


Fig.  542. 


the  cuspid  by  passing  between  it  and  the  lateral.  Dummies  are 
then  fitted  and  soldered  together,  placed  in  position,  and  joined 
to  the  attachments  with  wax  cement.  The  bridge  is  then  removed 
from  the  model,  invested,  and  soldered  together.  In  the  removal 
of  this  style  of  work  from  the  mouth  or  from  a  model,  should  the 
wax  not  hold  the  parts  reliably  together,  plaster  should  be  placed 
over  them,  so  that  when  removed  they  can  be  accurately  read- 
justed in  the  plaster.  Connection  with  the  attachment  is  only  to 
be  made  at  the  collar  section.  The  gold  crown  and  fusible  metal 
are  then  separated  from  the  model  and  the  fusible  metal  removed 
from  the  crown  in  the  manner  described  on  page  276. 

The  molar  crown  and  the  bridge  are  then  fitted  to  the  mouth. 
The  crown  is  next  cemented  on  the  molar  and  the  bridge  im- 
mediately adjusted  over  it,  pressed  into  position,  and  allowed  to 
remain  until  the  cement  has  set.     The  partial  cap  section  of  the 


REMOVABLE  AND  DETACHABLE  BRIDGE-WORK.  281 

attachments  is  burnished  down  on  the  bicuspid  and  the  gold  crown 
on  the  molar,  while  the  bridge  is  kept  firmly  pressed  against  the 
gums.  The  bridge  is  then  removed,  invested,  and  the  partial  cap 
sections  made  rigid  by  flowing  gold  solder  over  them.  The  final 
trimming,  finishing,  and  polishing  of  the  bridge  are  then  per- 
formed, and  it  is  ready  for  insertion. 

The  procedure  in  the  case  described  can  be  varied  by  making 
the  entire  model  of  fusible  metal,  or  by  placing  a  little  wax  in 
the  interior  of  the  grinding-surface  of  the  gold  crown,  making 
a  plaster  model,  removing  the  gold  crown  and  filling  it  with 
fusible  metal,  making  the  attachment,  and  replacing  the  gold 
crown  on  the  model.  The  cuspid  attachment  can  be  formed  on  a 
fusible-metal  cast  of  the  tooth. 

Fig.  543. 


The  methods  of  construction  as  above  given  may  be  still  further 
varied  by  first  forming  the  gold  crown  and  attachments  to  it  and 
the  collar  attachment  for  the  cuspid,  fitting  them  in  position  in 
the  mouth,  taking  a  plaster  impression  which  will  remove  them 
in  position,  and  then  making  a  model  of  plaster  and  calcined 
marble-dust.  On  this  the  dummies  can  be  fitted  and  soldered  to 
the  attachments.  The  gold  crown  is  to  be  removed  from  the 
model  after  the  position  of  the  attachment  on  it  is  secured  by  the 
investment  material,  and  the  cavity  thus  formed  is  then  to  be 
filled  with  more  investment  material.  This  is  probably  the 
method  most  practiced. 

Removable  bridge-work  is  best  constructed  with  the  bases  of 
the  dummy  teeth  pressing  firmly  on  the  tissue  of  the  gum,  or 
resting  on  a  saddle  of  platinum  the  size  of  the  base  of  the  artificial 
teeth.    If  the  collar  of  the  molar  attachment  should  prove  difficult 


282  CROWN-,  BRIDGE-,  AXD  PORCELAIN -WORK. 

to  remove  from  off  the  gold  crown  when  first  inserted,  it  should 
be  slit  at  the  posterior  section,  slightly  expanded,  and  reunited 
with  solder,  when  the  cap  sections  of  the  attachments  are  stiffened 
in  the  final  process  of  soldering.  A  small  piece  of  gold  plate  can 
lie  inserted  in  the  aperture  of  the  collar  to  aid  the  gold  to  unite 
the  ends. 

In  Fig.  543  is  illustrated  a  form  of  removable  bridge-work  that 
could  be  constructed  for  a  favorable  case.  In  the  construction,  a 
gold  crown  is  made  for  the  molar,  with  a  removable  gold  cap 
and  collar  attachment  and  a  removable  cuspid  crown,  with  a 
cap  and  a  tube  cemented  in  the  root-canal  for  the  cuspid.  The 
crowns  are  adjusted  in  position  in  the  mouth  and  an  impression 
and  bite  are  taken  in  plaster.  When  removed  from  the  mouth, 
the  crowns  and  attachments  are  to  be  replaced  in  position  in  the 

Fig.  544. 


impression,  and  a  model  of  plaster  and  calcined  marble-dust  made, 
and  also  an  articulating  model  in  plaster.  The  lateral  and  bicus- 
pid and  molar  dummy  teeth  are  next  fitted  in  proper  position  on 
the  model.  A  piece  of  pure  gold,  or  thin  platinum,  is  fitted 
against  the  lateral,  and  burnished  over  the  palato-approximal  side 
of  the  central  to  form  the  flange.  The  case  is  then  invested,  the 
gold  crown  slipped  out  of  the  attachment,  the  place  it  occupied  is 
filled  with  additional  investment  material,  and  the  parts  are  all 
soldered  together.  The  construction  can  be  varied  by  first  making 
the  bridge  from  the  molar  to  the  cuspid,  and  then  adding  the 
lateral  and  flange.  When  finished,  a  suitable  quantity  of  cement 
is  placed  in  the  gold  crown,  the  crown  is  fitted  on  the  molar,  the 
bridge  adjusted  in  position,  and  the  teeth  occluded  and  so  allowed 
to  remain  until  the  cement  sets.  Removable  bridges  for  cases 
such  a?  that  just  described  require  deep  root-canals  for  the  posts 
and  teeth  of  considerable  length  for  the  collar  attachments,  for 
proper  retention. 


REMOVABLE  AND  DETACHABLE  BRIDGE-WORK. 


283 


The  denture  illustrated  in  Fig.  544,  a  case  of  Dr.  A.  S.  Rich- 
mond's,  was  made  to  restore  a  loss  of  teeth  which  is  frequently 
met  with,  but  one  not  suitable  for  the  insertion  of  cemented 
bridge-work.  The  application  of  a  removable  denture  combin- 
ing bridge-  and  plate-work  is  a  method  possessing  some  advantages 
over  some  ordinarily  practiced.  In  brief,  the  constructive  details 
are :  A  connecting  bar  is  formed  as  described  on  page  278.  After 
the  bar  is  formed  the  pure  gold  is  extended  over  the  cuspid  and 
bicuspid  and  gold  clasp  attachments  or  collars  made  connected 
with  the  bar.  The  bar  and  clasp  or  collar  attachments  are  inserted 
in  the  mouth,  and  an  impression  taken  in  plaster.     Two  pieces  of 

Fig.  545. 


sheet  lead,  about  Xo.  26  gage,  are  placed  on  the  surface  of  the 
impression  where  the  saddles  are  to  rest,  for  the  purpose  of  causing 
an  equal  displacement  on  the  plaster  model  and  thus  securing 
an  even  pressure  for  the  saddles  on  the  alveolar  ridge.  (See  page 
219.)  A  model  is  next  made  with  the  attachments  and  bar  on  it  in 
position.  Metal  casts  are  also  made  of  the  parts  at  A  A,  Fig.  545, 
and  two  platinum  plates  struck  up.  The  teeth  are  then  arranged 
in  position,  the  bicuspids  resting  on  the  gums  and  the  molars  on 
the  two  plates  or  saddles,  and  the  denture  completed  as  shown  in 
the  illustration.  In  this  case  the  extension  of  the  saddle,  so  as  to 
cover  the  alveolar  ridge  under  the  bicuspids,  would  have  afforded 
more  support  and  without  perceptibly  increasing  the  size  of  the 
denture.  (See  Removable  Plate  Bridge-Work,  Part  III,  Chapter 
XII.) 

20 


284 


CROWN-,  BRIDGE-,  AXD  PORCELAIN -WORK. 


Removable  bridge-work  offers  peculiar  advantages  for  artificial 
replacement  of  lower  incisors  in  cases  similar  to  that  illustrated  in 
Fig.  546.  A  portion  of  the  contour  of  the  approximal  sides  of  the 
right  cuspid  is  removed.  Shell  caps  for  the  right  and  left  cuspids 
are  then  formed  of  pure  gold,  Ko.  36  gage,  reaching  nearly  to  the 
margin  of  the  gum.  The  caps  are  encircled  with  a  slightly  nar- 
rower piece  of  stiff  gold  plate  or  clasp-metal,  about  ISTo.  36  or 
37  gage,  which  is  soldered  to  the  caps  as  described  on  page  275 
in  the  construction  of  molar  partial  caps.  The  caps  are  next 
adjusted  in  the  mouth,  and  an  impression  and  bite  taken  in 
plaster  and  the  caps  removed  in  it. 

A  model  of  about  three  parts  plaster  and  one  of  marble-dust  and 
an  articulation  in  plaster  are  then  made.  Porcelain  incisor  teeth 
with  straight  pins  are  fitted  in  position,  backed,' and  a  broad  bar  ex- 

FiG.  546. 


tending  from  the  linguo-approximal  side  of  the  gold  cap  on  the  left 
cuspid  around  to  the  distal  side  of  the  lateral  is  formed  of  a  strip 
of  platinum,  adapted  to  the  parts,  overlaid,  and  soldered  to  a 
slightly  narrower  strip  of  gold  clasp-plate.  The  different  portions 
are  then  cemented  together  with  wax,  invested  on  the  model,  and 
properly  united  with  solder.  When  finished  and  inserted  in  the 
mouth,  it  constitutes  a  denture  that  can  be  worn  without  incon- 
venience by  the  patient,  and  removed  daily  and  cleansed,  which 
last  especially  is  a  great  advantage,  as  in  a  case  like  this  the  teeth 
replaced  have  usually  been  lost  by  recession  of  the  gums  and  those 
remaining  are  often  inclined  to  be  affected  by  the  same  trouble. 
The  natural  teeth,  if  loose,  are  in  a  measure  steadied  and  supported 
by  the  appliance. 

In  the  case  represented  in  Fig.  547,  gold  crowns  with  remov- 
able partial  cap  and  collar  attachments  are  made  for  the  molar 
and  bicuspid,  and  removable  crowns  with  partial  collars  at  the 


REMOVABLE  AND  DETACHABLE  BRIDGE-WORK. 


l'>:. 


palatal  sides  for  the  centrals  and  cuspid.  The  right  central  can 
be  capped  and  the  crown  fitted  over  it  without  a  post,  if,  in  the 
opinion  of  the  operator,  the  posts  in  the  other  two  crowns  will 
afford  ample  security. 

The  root-caps  of  the  centrals  and  cuspid  are  cemented  on  each 

Fig.  547. 


root  with  oxyphosphate.     The  central  crowns  are  cemented  to- 
gether with  wax,  adjusted  in  position,  covered  with  a  small  quan- 


Fig.  548. 


tity  of  investment  material,  removed,  more  investment  material 
added,  and  the  crowns  soldered  together. 

The  centrals  and  the  cuspid  are  then  adjusted  in  the  mouth, 
a  lateral  is  backed,  fitted,  and  waxed  between  them  in  position, 
the  whole  removed  in  investment  material,  and  the  process  of  in- 


286 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


vesting  and  soldering  proceeded  with  to  join  the  parts  as  before 
described.  This  bridge  of  four  teeth  is  fitted  to  the  mouth,  and 
the  points  of  the  posts  trimmed  on  the  side  and  in  the  direction 
which  will  best  favor  their  entrance  into  the  tubes  in  each  root, 
so  that  the  bridge  will  readily  slip  into  position.  The  dummy 
bicuspids  and  molar  on  the  right  side  between  the  cuspid  and 
molar  are  then  added  by  first  taking  an  impression  and  bite  of  that 
section,  and  then  proceeding  with  the  construction  as  described  in 
previous  cases.  The  section  of  the  bridge  with  the  extension  on 
the  left  side  is  next  added  in  a  similar  manner  by  taking  an  im- 

FlG.  549. 


pression  of  the  part  while  the  portion  of  the  bridge  already  con- 
structed is  in  position,  removing  bridge  and  impression  together  as 
described  on  page  283,  and  making  a  model.  A  piece  of  pure 
gold  or  platinum  is  shaped  to  the  model  by  alternately  burnishing 
and  annealing,  to  form  a  base  for  the  molar.  The  one  molar  will 
exert  as  much  leverage  on  the  abutment  of  the  bridge  in  mastica- 
tion as  can  safely  be  borne. 

Fig.  548  shows  the  bridge  completed,  and  Fig.  549  the  piece 
in  position.  Very  long  substantial  abutments  are  required  for  the 
support  of  a  piece  of  bridge-work  constructed  as  above  described. 
At  the  present  time  the  "Griswold"  attachments  are  generally 
used  in  such  cases.     (See  page  309.) 


CHAP  TEE    XII. 

Removable  Plate  Bridge- "Work. 

form    of    construction— methods    of    construction— various 
styles— dr.  bonwills  method— dr.  davenport's  case. 

Form  of  Construction. — In  this  style  of  work  a  plate  is  used 
to  span  the  space  and  support  the  artificial  teeth  between  the  abut- 
ments. Attachments  similar  to  those  used  in  connection  with  re- 
movable bridge-work  are  also  applicable  to  removable  plate- 
bridges.  .Removable  plate  bridge-work  is  really  plate-work  se- 
cured in  position  by  removable  bridge-work  attachments,  and  is 
intended  to  combine  in  a  denture  the  advantages  of  both  systems. 
In  the  construction  of  removable  plate  bridge-work,  removable 
crowns,  caps,  or  attachments  are  made  for  the  supporting  teeth  in 
the  same  manner  as  for  removable  bridge-work,  though  clasp  at- 
tachments may  be  somewhat  more  freely  used. 

Methods  of  Construction — An  impression  of  the  part  is  taken, 
from  which  a  plaster  model  is  made.  On  the  model  an  outline  of 
the  size  of  the  required  plate  is  marked  and  the  edge  of  the  space 
scraped  sufficiently  to  insure  a  slight  pressure  for  its  margins.  A 
metallic  die  and  counter-die  are  cast,  and  a  gold  plate  of  the  proper 
size  swaged. 

In  all  forms  of  removable  plate  bridge-work,  when  the  attach- 
ments are  brought  to  their  proper  position  on  the  crowns  or  teeth 
supporting  them,  the  plate  constituting  the  bridge  should  not 
merely  rest  on  but  should  press  on  the  alveolar  border  intervening 
between  them,  especially  when  first  constructed.  This  result  is 
obtained  by  methods  practiced  in  the  application  of  the  plate  in 
the  following  manner :  Pressure  is  exerted  along  the  central  por- 
tion of  the  plate  with  a  broad-pointed  instrument  which  will  not 
slip.  Take  a  britannia  impression-tray  and  cut  a  slot  in  the  side  ex- 
tending to  the  center  of  the  bottom  of  the  cup,  of  such  a  size  and 
shape  as  will  permit  the  cup  to  be  inserted  and  an  impression  taken 
without  interfering  with  the  instrument  when  held  against  the 

287 


288 


CROWN-,  BRIDGE-,  AND  PORCELAIN-MORE. 


plate.  Fill  the  impression-tray  with  plaster.  Exert  direct  pressure 
on  the  plate  with  the  instrument  sufficient  to  whiten  the  tissue  at 
the  edges  where  the  model  was  scraped  and  insert  the  impression- 
tray  and  plaster.  Maintain  the  pressure  with  the  instrument  until 
the  plaster  has  set,  then  remove  all  together,  including  plate,  at- 
tachments, and  instrument,  and  run  a  plaster  model.  On  the  re- 
moval of  the  model  the  plate  and  attachments  will  be  found  on 
it  in  the  same  relative  position  as  they  were  in  the  mouth. 
Cement  the  attachments  to  the  plate  with  wax,  remove,  invest, 
and  solder  together. 

Another  method  is  to  make  the  model  of  marble-dust  and 
plaster  and  solder  the  plate  and  attachments  together  on  the  model 
and  so  avoid  their  removal  until  united. 


The  plate  and  attachments  are  next  fitted  in  the  mouth,  wax 
is  placed  on  the  plate,  and  a  "bite"  taken  in  the  usual  manner. 
An  articulating  model  is  made,  and  also  a  model  run  for  the 
plate  and  attachments  to  rest  on,  if  the  original  model  has  been 
destroyed  by  investing  the  plate  and  attachments  on  it  wThen  they 
were  soldered  together. 

Pressure  of  the  plate  on  the  tissues  in  cases  of  small  plate  bridge- 
work  can  be  obtained,  but  less  reliably,  in  the  following  manner : 
Cement  the  attachments  to  the  plate  with  sticky  wax,  adjust  in 
the  mouth,  press  on  the  plate,  chill  the  wax  with  ice-water,  re- 
move, invest,  and  solder  the  attachments  to  the  plate. 

Another  method  is :  First  strike  upon  a  die  of  the  case  a  plate 
of  lead,  ISTo.  24  to  32  gage,  according  to  the  hardness  of  the  tis- 
sues and  the  pressure  desired.     Take  a  plaster  impression  with 


REMOVABLE   PLATE  BUWU E-WORK. 


289 


the  attachments  in  position.  Place  the  lead  plate  in  the  plaster 
impression  and  run  a  model.  When  the  model  is  made,  remove 
the  lead  and  substitute  gold  plate  in  its  place  in  position  on  the 
model  and  connect  the  attachments  with  solder.  By  this  method 
a  uniform  pressure  of  the  plate  on  the  membranes  to  any  de- 
sired degree  is  obtained.  The  first  described  method  is  generally 
the  best  one  to  pursue. 

The  plate  tand  attachments  having  been  united,  the  case  is  then 
finished  with  plain  or  gum  teeth,  attached  with  vulcanite  or  gold, 
as  circumstances  may  suggest.  Should  a  clasp  attachment  cause 
decay  or  abrasion  of  a  tooth,  the  part  can  be  excavated  to  a  slight 

Fig.  552. 


depth  under  the  clasp,  and  tilled  with  gold.  This  is  best  done  by 
making  a  few  retaining-pits,  filling  them  with  a  hand-plugger,  and 
then  inserting  the  main  body  of  the  gold  in  the  ordinary  manner, 
the  Herbst  method  being  useful  in  condensing  the  foil.  Such  a 
filling  inserted  at  any  time  will  prevent  injury  from  a  clasp.  A 
denture  of  this  style  can  be  made  to  pass  intervening  teeth. 

Various  Styles.- — In  the  artificial  replacement  of  the  lower 
teeth  in  a  case  such  as  is  illustrated  in  Figs.  550,  551,  a  plate- 
bridge  possesses  many  advantages.  In  the  construction  of  such  a 
denture,  the  teeth  are  first  properly  shaped.  Gold  crowns  (Fig. 
552),  with  sides  as  nearly  as  possible  parallel  the  one  with  the 
other,  are  then  made  and  fitted  to  the  bicuspid  and  molar.     This 


290  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

operation  is  frequently  facilitated  by  shaping  the  external  surface 
of  the  crown  with  metal.  On  the  crowns,  at  the  buccal  sides  (Fig. 
552),  a  narrow  shoulder  (A)  is  constructed  to  sustain  the  collars 
and  bridge  in  position.  In  some  cases  this  shoulder  is  placed  on 
the  approximal  side  to  better  advantage.  Collars  B  B,  Fig.  552, 
reaching  from  the  cervical  to  the  occluding  edge,  are  fitted  to  these 
crowns. 

The  collars,  though  fitting  accurately,  should  move  easily  over 
the  crowns,  as  they  can  be  readily  tightened  when  the  case  is 
finished.  If  the  collar  is  troublesome  to  adjust  and  remove,  cut 
the  side  opposite  to  that  attached  to  the  plate,  and  spring  it  open 
a  little.  After  fitting  the  teeth  it  can  be  again  united  when  they 
are  being  soldered.      This  collar  and  shoulder  form  a  support 

Fig.  554. 


in  some  respects  preferable  to  a  partial  or  an  entire  double  cap, 
being  less  difficult  to  keep  clean.  A  collar  is  more  easily  con- 
structed, and  also  permits  the  position  of  the  bridge  to  be  altered 
by  the  removal  of  a  little  of  the  shoulder  or  of  the  cervical  edge  of 
the  collar,  and  is  a  secure  but  less  rigid  attachment  than  is  pro- 
vided by  other  methods.  The  other  constructive  details  of  this 
denture  are  conducted  in  accordance  with  removable  bridge-work 
methods.  In  a  case  such  as  just  described,  the  artificial  first  bi- 
cuspid is  best  attached  with  gold  to  the  side  of  the  removable  collar 
which  fits  on  the  second  bicuspid,  and  the  molars  with  vulcanite 
to  the  plate.  If  iridio-platinum  plate  is  used  in  the  construction 
instead  of  gold,  and  platinum  solder  used  for  soldering,  porcelain 
body  can  be  used.  When  ready  to  be  inserted,  the  crowns  are 
adjusted  with  cement,  and  then  the  bridge,  which  is  left  in  posi- 
tion until  the  cement  sets.     By  burnishing  the  collars  they  can 


REMOVABLE  PLATE  BRIDGE-WORK. 


291 


be  made  to  clasp  the  crowns  as  firmly  as  desired.     Fig.  554  shows 
the  denture  in  position. 

Figs.  555  and  556  represent  an  upper  removable  plate-bridge. 
In  its  construction  the  cuspid  roots  are  first  capped,  tubed,  and 
pivoted,  and  the  molars  crowned.     The  plate  intended  to  connect 

Fig.  555. 


the  abutments  is  then  adjusted  in  position  as  has  been  described. 
An  impression  is  next  taken  and  a  model  made.  The  cuspids 
are  then  double-capped  and  collars  formed  on  the  molar  crowns. 
The  molar  collars  are  first  soldered  to  the  plate.  The  molar 
crowns  are  removed  from  the  model,  placed  in  the  mouth,  and  the 
collars  on  the  plate  fitted  over  them.  The  plate  is  pressed  firmly 
against  the  tissues,  and  the  line  of  the  edge  of  the  collars  toward 

Fig.  556. 


the  gum-margin  marked  with  a  sharp  instrument  on  the  buccal 
surfaces  of  the  gold  crowns,  and  the  crowns  removed.  At  the 
lines  marked  on  the  gold  crowns  shoulders,  such  as  are  shown  in 
Fig.  552,  are  next  soldered.  The  plate  and  all  the  caps  are  again 
adjusted  in  the  mouth.     The  plate  is  pressed  firmly  against  the 


292 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 


tissues,  the  double  caps  on  the  cuspids  attached  to  the  plate 
with  cement,  or  plaster  instead  can  be  placed  over  them  and  the 
adjacent  surface  of  the  plate,  and  plate  and  cuspid  double  caps 
removed,  invested,  and  soldered  to  plate.  The  artificial  teeth  are 
attached  with  vulcanite,  the  gum  section  being  formed  with  pink. 
In  order  to  avoid  any  warping,  which  might  readily  occur  in  the 
construction  of  so  large  a  denture  as  this,  the  plate  may  at  first  be 
swaged  up,  as  in  ordinary  artificial  dentures,  to  cover  the  entire 
hard  palate.  A  shallow  groove  can  be  made  around  the  palatal 
side  on  the  plaster  model  where  the  plate  is  to  extend.     This 


groove  being  reproduced  in  the  metallic  die  will  also  form  a  groove 
in  the  swaged  gold  plate.  After  the  final  soldering  the  plate  can 
be  cut  along  the  line  of  this  groove,  the  portion  covering  the  palate 
being  removed.  The  groove  will  insure  a  close  fit  for  the  palatal 
edge  of  the  plate. 

In  the  case  represented  in  Tig.  557  the  natural  teeth  were  very 
short.  The  posterior  approximal  side  of  the  molar  was  decayed 
to  such  an  extent  that  the  pulp  was  nearly  exposed,  and  con- 
siderable irritation  of  the  investing  gum-tissue  had  been  caused 
by  the  clasp  of  a  plate  worn  by  the  patient  working  upward  against 
it.  The  patient  declined  to  have  a  plate  made  which  would  ex- 
tend across  the  palate.  The  lateral  was  hardly  strong  enough  to 
support  a  permanent  bridge.     The  molar  was  capped  with  gold, 


REMOVABLE  PLATE  BRIDGE-WORK. 


293 


and  a  removable  collar  was  made  to  lit  over  the  gold  crown  and 
rest  on  a  spur  placed  on  the  mesial  side.  The  lateral  was  notched 
and  clasped  for  the  anterior  support.  Tigs.  55S  and  559  are  two 
views  of  the  appliance  in  position.1 

Pig.  560  represents  a  case  in  which  the  bicuspids  and  a  molar 
are  replaced,  and  also  a  central,  on  an  extension  of  the  plate, 


Fig.  559. 


the  cuspid  being  nearly  encircled  by  a  clasp  with  a  shoulder  rest- 
ing on  the  palatal  section  of  the  tooth.  Fig.  501  shows  the  den- 
ture in  position. 

Fig.  562  represents  a  case  in  which  a  bridge-plate  was  inserted 
without  crowning  either  of  the  abutments.  The  clasp  of  a  plate 
which  had  been  worn  for  some  years  had  worked  upward  and 
abraded  the  distal  section  of  the  cuspid  to  such  an  extent  as  to 
expose  a  large  portion  of  the  root  and  superinduce  decay.     The 


This  denture  the  last  time  seen  had  been  worn  thirteen  years. 


294 


GROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


cavity  was  filled  with  gold,  and  the  gingival  border,  by  treatment, 
brought  nearly  to  its  normal  position  on  the  tooth.       A  plate- 


Fig.  560. 


Fig.  561. 


bridge,  such  as  is  represented  in  Figs.  563,  A,  and  563,  B,  was  con- 
structed. Clasps,  with  flanges  resting  on  little  shoulders  formed 
at  A  A,  Fig.  562,  support  and  retain  it.     A  flange  such  as  was 


Fig.  562. 


Fig.  563,  A. 


Fig.  563,  B. 


used  in  this  case  is  best  made  subsequent  to  the  construction  of  the 
plate  and  clasps,  by  burnishing  a  piece  of  platinum  foil  in  the 


REMOVABLE  PLATE  BRIDGE-WORK. 


295 


mouth  to  the  form  of  the  shoulder  and  the  side  of  the  tooth  upon 
which  it  is  to  rest,  adjusting  the  clasp  over  it,  and  cementing  with 
wax,  then  removing,  investing,  and  soldering.  Wherever  the 
platinum  is  placed,  the  solder  will  flow  and  fill  all  the  space  be- 
tween it  and  the  clasp.  This  gives  the  clasp  the  exact  form  of  the 
tooth. 

Fig.  564  shows  the  denture  finished  and  in  position.     If  the 
teeth  are  dense  in  structure,  an  attachment  of  metal  held  in  proper 

Fig.  564. 


position  against  the  lower  portion  of  a  natural  crown  will  be  worn 
a  long  while  before  it  causes  injury  to  the  parts.  Filling,  or 
crowning,  if  necessary,  can  be  resorted  to  subsequently. 

By  a  correct  application  of  the  methods  just  explained  and 
illustrated,  a  piece  of  removable  bridge-work  of  this  style  can 
be  devised  for  many  cases. 

Inlay  Attachment. — Fig.  5G5,  A,  illustrates  Dr.  F.  A.  Peeso's 
inlay  attachment.      The  main  support  of  the  bridge  is  obtained 


Fig.  565,  A. 


by  the  use  of  a  split  pin  in  a  tube  inserted  in  an  inlay  cemented 
in  the  mesial  section  of  the  molar.  The  anterior  end  of  the 
bridge  is  supported  and  steadied  by  a  substantial  hooked  wire 
spur  which  rests  in  a  groove  in  a  filling  inserted  in  the  bicuspid. 
The  method  of  construction  is  as  follows :  The  molar  is  de- 
vitalized and  cut  out  on  the  occlusal  surface  about  one-half  its 
length  and  down  on  the  mesial  side  sufficient  to  allow  space  for 


9<J(5  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

a  heavy  round  bar  of  about  No.  13  gage  with  a  good  thickness 
of  gold  between  it  and  the  walls.  The  shape  to  be  given  the 
cavity  is  illustrated  in  Figs.  565,  B,  and  565,  C,  which  show  the 
sides  curved  and  non-retentive.  The  pulp-chamber  is  filled  with 
gutta-percha.  Pure  gold,  No.  34  to  35  gage,  is  then  burnished 
into  the  cavity  as  for  an  inlay,  care  being  taken  to  have  the 
margin  perfect.  A  hole  is  next  made  through  the  matrix  near 
the  distal  end  into  the  gutta-percha  to  the  floor  of  the  pulp 
chamber.  In  this  hole  is  placed  an  iridio-platinum  tube  large 
enough  to  take  a  No.  13  or  No.  14  wire  pin.  The  tube  is  waxed 
securely  to  the  matrix  and  removed.  A  piece  of  pure  gold  is 
placed  across  the  front  of  the  matrix  against  the  wax  so  that 
it  can  be  entirely  filled  at  that  point  in  the  soldering.  The  ma- 
trix is  next  invested  and  filled  with  22-carat  gold.  This  forms  a 
gold  inlay  with  the  tube  in  position  extending  through  it,  Fig. 
565,  D. 

Fig.  565,  B.  Fig.  565,  C.  Fig.  565,  D.  Fig.  565,  E. 


L 

A  groove  is  next  cut  from  the  orifice  of  the  tube  through  the 
inlay  to  this  mesial  side.  The  bulk  of  the  cutting  is  quickly  done 
with  a  thin  round-edge  carborundum  wheel.  (Fig.  565,  E.) 
The  groove  can  then  be  finished  with  a  fissure-bur  of  the  same 
size  as,  or  slightly  larger  than,  the  inside  diameter  of  the  tube. 
The  entrance  to  the  tube  is  to  be  slightly  rounded  with  an  oval- 
shaped  finishing-bur,  a  slight  downward  curve  being  given  to  the 
mesial  side  to  permit  the  bent  portion  of  the  bar  to  be  more 
easily  set  into  the  groove  and  to  avoid  the  projection  of  the  re- 
mainder above  the  surface  of  the  inlay  or  the  cusps  of  the 
dummy.  Fig.  565,  F,  shows  a  section  of  the  inlay  and  tube  in 
position  in  the  tooth  with  the  bar  and  pin  in  place. 

The  combined  bar  and  pin  is  made  of  half-round  iridio-plati- 
num or  platinized  gold  wire,  bent  double  and  soldered  to  within 
about  a  quarter  of  an  inch  from  the  end.  (Fig.  565,  G.)  A 
flake  of  isinglass  should  be  inserted  between  the  ends  of  the 
wire  at  the  part  to  remain  unsoldered.      It  is  next  trimmed  or 


R  E  MOV  A  II L  K    PL  A  TE    BR  ID  GE-M<>h'l\. 


297 


turned  to  exactly  fill  the  tube  and  groove  and  then  bent  and 
fitted  to  lie  closely  in  the  groove  and  filed  so  the  pin  end  can  be 
slightly  opened  to  give  it  a  spring  that  will  hold  the  piece  firmly 
in  position. 

The  bicuspid  is  prepared  with  the  grooved  and  countersunk 
filling.  The  gold  must  be  very  dense  and  well  anchored.  The 
antagonizing  tooth  should  be  trimmed  to  favor  the  filling  and  bar 
in  occlusion. 


Fig.  505,  F. 


Fig.  565,  G. 


Fig.  565,  H. 


The  inlay  with  the  pin  in  position  is  next  placed  in  the  tooth 
and  a  combined  impression  and  articulation  taken  in  plaster, 
the  inlay  coming  away  in  the  impression  on  removal.  A  model 
and  articulating  model  are  made,  which  will  give  the  position  of 
the  gold  inlay,  and  show  the  groove  and  slot  in  the  bicuspid. 
The  spur  to  fit  the  latter  is  to  be  made  of  either  iridio-platinum 

Fig.  565.  I. 


or  platinized  gold  wire,  Ko.  M  to  10  gage.  The  construction  of 
the  bridge  is  next  proceeded  with  and  the  bar  and  spur  are  solidly 
soldered  into  it.  (Fig.  565,  H.)  The  sides  of  the  gold  inlay 
are  to  be  slightly  grooved  or  roughened.  It  is  then  cemented 
to  place  in  the  molar  while  in  position  on  the  bridge  as  though 
it  were  a  fixed  piece.  The  spur  resting  in  the  groove  in  the 
bicuspid  filling  with  the  point  in  the  slot,  prevents  lateral  motion 
of  the  bridge  and  spreading  of  the  teeth. 


298  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Inlay  attachments  are  applicable  to  a  variety  of  small  remov- 
able bridges  supported  by  central  incisor,  cuspid,  or  bicuspid 
teeth.  Fig.  565,  I,  shows  the  splint  pin  and  tube  used  in  con- 
nection with  a  removable  double  cap-crown  on  a  molar  and  out- 
lines the  construction. 

Dr.  Bonwill's  Method.1 — The  special  feature  of  this  method  is, 
the  manner  of  connecting  the  clasp  attached  to  the  plate  with 
a  piece  of  stout  gold  and  platinum  wire  on  the  side  of  the  tooth 
offering  the  least  resistance  to  the  insertion  and  removal  of  the 
clasp.  This,  for  instance,  should  be  on  the  buccal  side  of  a  lower 
molar  if  it  tips  inward  or  forward.  The  clasp  is  thus  left  free  to 
spring  over  any  portion  of  the  crown  out  of  line. 

The  clasp  is  surmounted  with  a  flange  or  spur  placed  at  a  point 
free  of  the  occluding  teeth,  and  the  plate  is  made  of  heavy  gold 
plate  or  of  two  thin  plates  soldered  together.  A  description  of  the 
following  practical  cases  will  explain  the  method: 

Tig.  566  is  a  model  for  the  first  upper  bicuspid,  left  side.  A 
filling  of  gold  was  placed  in  the  distal  surface  of  the  natural 
cuspid,  with  a  hole,  c,  drilled  into  the  filling  for  the  pin  c,  Fig. 
567.  The  second  bicuspid  had  also  a  large  amalgam  filling, 
around  which  the  clasp  was  placed,  so  that  it  would  not  show 
in  the  mouth.  Fig.  567  shows  the  plate  with  a  tube-tooth  or  porce- 
lain crown  thereon,  held  by  a  post  soldered  to  the  plate.  The 
clasp  has  a  flange  attached  to  it  at  h;  i  is  a  heavy  platinized 
gold  bar,  showing  how  it  forms  a  free  attachment  between  plate 
and  clasp;  c  is  a  pin,  soldered  directly  to  the  plate,  which  enters 
the  hole  in  the  gold  filling  shown  at  c  in  Fig.  566. 

Fig.  568  is  a  skeleton  plate  with  the  attachments  without  the 
tooth  made  for  the  case- — left  side,  lower  jaw — shown  in  Fig.  570. 
e  and  e,  Fig.  568,  are  flanges  to  prevent  the  plate  pressing  too 
hard  on  the  gum.  One  rests  on  the  molar  independent  of  the 
clasp,  and  the  other  on  the  bicuspid.  A  small  spur  is  placed 
under  the  flange  that  is  to  rest  on  the  bicuspid  to  fit  in  a  groove 
in  an  amalgam  filling  shown  at  d,  Fig.  570,  to  keep  the  anterior 
portion  of  the  plate  in  position.  The  clasp  is  connected  to  the 
plate  at  the  lingual  side  by  the  bar  marked  i.  Fig.  569  shows 
the  finished  case  with  the  artificial  crown  cemented  over  the  pins 
or  vulcanized  on. 

1  International  Dental  Journal,   vol.  xiv,   page  94. 


REMOVABLE  PLA  TE  BRIDGE-  WORK. 


299 


Fig.  571  shows  the  replacement  of  a  second  bicuspid,  right 
side,  lower  jaw.  The  bar  i  is  soldered  to  the  plate  and  clasp 
on  the  buccal  side  of  the  first  molar.  The  artificial  tooth  is  made 
entirely  of  gold,  and  the  flange  resting  on  the  first  bicuspid  is 
soldered  directly  to  it.  The  anterior  surface  of  the  gold  tooth  is 
made  concave  to  fit  the  distal  surface  of  the  first  bicuspid  and 
so  prevent  lateral  movement. 

In  this  case  a  gold  crown  is  used  as  the  artificial  tooth,  as  it 
facilitates  the  soldering,  adds  to  the  strength,  is  easy  to  repair, 
and  is  not  seen.  The  rear  flange,  which  rests  on  the  molar,  might 
have  been  soldered  to  the  gold  tooth  also,  and  less  strain  would 
thus  come  on  the  clasp. 


Fig.  566. 


Fig.  567. 


Fig.  568. 


Fig.  569. 


Fig.  570. 


Fig.  571. 


Dr.  Davenport's  Case — This  case  of  Dr.  J.  L.  Davenport's  is 
presented  to  show  the  various  methods  which  may  be  practically 
adopted  in  the  construction  of  plate-bridges. 

"The  patient  was  a  gentleman  about  fifty-five  years  of  age. 
The  upper  jaw  contained  the  six  front  teeth,  the  three  molars 
on  the  right  side,  and  the  first  bicuspid  on  the  left.  The  lower 
jaw  contained  all  but  the  left  central  incisor,  the  second  bicuspid, 
the  three  molars  on  the  right  side,  and  the  first  and  third  molars 
of  the  left. 

"In  consequence  of  this  lack  of  occluding  back  teeth,  mastica- 
tion had  been  performed  solely  by  the  front  teeth,  causing  attri 

21 


300  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

tion  so  great  on  the  upper  ones  as  to  entirely  obliterate  their 
crowns,  while  the  lower  ones  suffered  but  little  loss,  as  will  be 
seen  by  reference  to  Fig.  572. 

"The  patient  had  managed  for  a  long  time  to  masticate,  though 
imperfectly,  upon  these  stumps,  but  latterly  could  eat  scarcely 
anything  but  soups  and  soft  foods. 

"The  restoration  of  the  lower  teeth  being  completed  to  the 
extent  of  about  one-eighth  of  an  inch  on  an  average,  to  make 
them  of  uniform  height,  my  attention  was  directed  to  the  upper 
incisors  and  cuspids,  nearly  all  of  which  I  found  with  dead  pulps, 
and  some  of  them  in  a  condition  of  active  abscess. 

"The  two  superior  cuspid  roots  were  dressed  down  nearly  to 
the  gum,  and  fitted  with  22-carat  gold  cap-crowns.     After  these 

Fig.  572. 


had  been  placed  in  position,  a  hole  was  drilled  through  each  cap 
of  a  size  suited  to  that  of  the  pulp-canal,  and  a  tube  of  iridium 
and  platinum  was  adjusted  in  the  root  and  cap  and  waxed  in 
position.  The  cap  and  tube  were  then  taken  off  and  soldered, 
great  care  being  taken  to  have  the  tubes  enter  both  roots  per- 
fectly parallel.  These  were  permanently  secured  in  the  roots 
with  gutta-percha,  and  to  prevent  the  caps  being  pulled  off  the 
top  of  each  tube  was  slit  down  a  trifle,  and  after  insertion  was  bent 
back  into  the  gutta-percha  with  a  warm  instrument. 

"The  incisor  roots  having  been  dressed  down  even  with  the 
gum  and  filled,  a  plaster  cast  was  taken  and  a  narrow  20-carat 
gold  plate  was  swaged  to  fit  over  the  ends  of  the  incisors  and  the 
capped  cuspids,  making  it  a  little  broader  where  it  had  to  rest 


i;i:\l(t\  ABLE  PL  177.    BRIDGE-WORK. 


;oi 


on  the  gum  back  of  the  first  left  bicuspid  root.  A  hole  in  the 
plate  was  then  made  to  expose  the  root  of  the  first  left  bicuspid. 
This  was  fitted  with  a  bifurcated  iridio-platinum  pin,  having 
notched  sides  and  a  hammered  head  upon  its  lower  end.  which 
came  down  below  the  root  about  three-eighths  of  an  inch. 

"A  thin  iridio-platinum  band  was  then  made  to  encircle  the 
root,  passing  just  under  the  gum  and  being  slightly  longer  than 
the  headed  pin.  This  band  was  perforated  with  two  rows  of 
holes;  from  without  inward,  giving  the  inner  surface  a  rough- 
ness similar  to  that  of  a  nutmeg-grater.  The  band  and  pin  were 
then  made  secure  to  the  root  with  a  non-shrinkable  copper  amal- 
gam. 

"Fig.  573  shows  the  upper  jaw  ready  for  the  plate. 

Fig.  -"iT.'i. 


"After  the  amalgam  had  become  hard  and  the  end  and  sides 
had  been  polished,  a  gold  crown  was  fitted  over  all  just  up  to 
the  margin  of  the  gum,  and  in  close  contact  with  the  end  of  the 
band  and  amalgam.  This  crown  was  loose  enough  to  admit  of 
its  sliding  on  and  off,  though  with  just  enough  friction  to  hold  it 
in  place  when  at  rest.  This  gold  crown  was  then  placed  in  posi- 
tion, the  plate  also  inserted,  and  hard  wax  used  to  firmly  join 
the  two  in  the  mouth.     They  were  then  removed  and  soldered. 

"Gold  pins  were  then  placed  through  holes  drilled  in  the  plate 
into  the  tubed  cuspids;  then  soldered  to  the  plate,  the  pins  being 


302 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


of  a  size  to  fit  the  tuhes  accurately.     The  plate  was  also  provided 
with  a  wide  clasp  encircling  the  first  molar  on  the  right. 

"The  plate  was  then  provided  with  a  gold  bar  about  one-eighth 
of  an  inch  wide,  occluding  perfectly  with  the  lower  teeth,  and 
plain  teeth  soldered  in  place,  hiding  the  bar,  and  just  meeting 
the  gum  in  front  of  the  incisor  roots.  The  plate  rested  squarely 
against  the  capped  cuspids,  each  of  which  showed  a  narrow  band 

Fig.  574. 


of  gold  when  the  plate  was  in  position.  As  finally  completed 
(see  Fig.  574),  this  was  the  most  perfectly  fitting  piece  I  ever 
inserted,  requiring  great  care  in  its  removal,  and  yet  by  a  little 
practice  the  gentleman  was  able  to  remove  and  replace  it  quite 
easily.     It  was  also  as  firm  as  any  permanent  bridge  could  have 


Fig.  575. 


been,  though  it  had  no  support  on  the  left  side  back  of  the  first 
bicuspid. 

"The  lower  jaw  was  supplied  with  a  double  20-carat  gold  plate, 
having  a  wide  clasp  on  the  first  right  bicuspid,  which,  after  being 
built  up,  presented  a  cone-shaped  top,  about  which  the  clasp 
fitted  so  as  to  rest  firmly  upon  the  end  of  the  tooth,  thus  pre- 
venting injury  to  the  gum  during  mastication. 


REMOVABLE   PLATE  BRIDGE-WORE. 


303 


"The  only  other  peculiarity  was  that  the  second  left  inferior 

molar,  being  abnormally  short,  though  well  formed  and  standing 

straight  upright,  was  fitted  with  a  wide  clasp,  extending  almost 

,  one-eighth  of  an  inch  about  the  tooth,  and  a  piece  of  gold  plate 

with  gold  cusps  was  soldered  into  this  clasp,  covering  the  molar 

Fig.  576. 


crown  and  occluding  with  the  molar  on  the  upper  plate.  (See 
Fig.  575.)  This  not  only  prevented  the  plate  from  being  bitten 
down  unpleasantly  on  the  gums  during  mastication,  but  enabled 
me  to  use  a  shorter  molar  upon  the  upper  than  I  otherwise  could 
have  done,  and  allowed  better  the  antero-posterior  and  lateral 
movements  of  the  jaws. 

"Fig.  576  shows  the  case  as  completed.''" 


CHAP  TEE    XIII. 

Special  Forms  of  Detachable  and  Removable  Bridge-Work. 

sectional  crown  methods:  dr.  winder's— dr.  spencer's— case 
of  dr.  alexander's— dr.  litch's  method— dr.  parrs  dovetail 
flange  attachment— the  griswold  system. 

A  description  of  a  few  special  forms  and  methods  of  con- 
structing detachable  and  removable  bridge-work  is  given  in  the 
following  pages,  as  practiced  by  the  introducers. 

Sectional  Crown  Methods. 

Dr.  Winder's. — In  this  method  the  crowns  forming  the  abut- 
ments are  constructed  in  sections,  the  bridge  being  attached  to  the 
detachable  section. 

Fig.  577. 


Figs.  577  and  578  illustrate  a  case  of  bridge-work  made  in  this 
manner.  The  collar  section  of  the  artificial  crown  is  capped  and 
cemented  on  the  natural  crown  or  root,  the  gold  forming  the 
occluding  portion  of  the  crown,  when  the  bridge  is  adjusted  in 
position,  being  secured  to  it  with  a  screw. 

In  constructing  this  style  of  bridge,  the  crowns  with  their  sec- 
tional occluding  surfaces  are  first  made  .and  placed  on  the  teeth 
or  roots  and  an  impression  and  articulation  are  taken  which  will 
remove  them  in  position.  A  model  and  articulating  model  are 
then  made.  The  teeth  or  dummies  are  then  formed  in  the  usual 
manner  and  cemented  with  wax  to  the  detachable  occluding  sec- 
304 


DETACHABLE  A\D  REMOVABLE  BRIDGE-WORK. 


305 


tious  of  the  crowns  and  the  screws  that  secure  them  loosened.  The 
dummies  and  the  removable  occluding  sections  are  removed  in 
investing  material,  in  an  impression-cup,  or  by  placing  the  invest- 
ing material  in  position  on  the  bridge,  leaving  the  collar  sections 
of  the  crowns  on  the  model.  After  being  removed,  more  investing 
material  is  added  and  the  bridge  and  crown  sections  soldered  to- 
gether. 

Fig.  578. 


The  occluding  surfaces  of  the  porcelain  can  be  capped  with 
gold  as  in  permanently  attached  bridge-work,  or  they  can  be 
formed  of  the  porcelain,  which  latter  lessens  the  labor  of  con- 
struction, as  the  bridge  is  easily  detached  from  the  abutments  for 
the  purpose  of  repair.  When  the  bridge  is  finished,  the  root  and 
collar  section  of  each  crown  is  first  cemented  on  in  position  in  the 
mouth;  the  surface  of  the  detachable  section  of  the  crown  ap- 


Fig.  579. 


Fig.  580. 


proximating  them  is  then  heated  and  the  surface  covered  with 
a  mere  film  of  gutta-percha.  The  bridge  is  then  adjusted  in  posi  ■ 
tion  and  secured  by  the  screws.  The  gutta-percha  prevents  the 
secretions  invading  the   interstices  between  the   sections  of  the 


Dr.  Spencer's. — Fig.  579  illustrates  another  method,  devised 
by  Dr.  "W.  R.  Spencer,  of  constructing  the  sections  of  the  crowns 


306 


CKOWN-.  BRIDGE-,  AM>  PORCELAIN -WORK. 


in  this  style  of  bridge-work.  The  part  A  slides  in  the  groove  B. 
The  dovetail  flange  A  is  made  of  a  thick  piece  of  plate,  fitted  to 
the  groove  B.  The  flange  A  is  soldered  to  a  piece  of  platinum 
adapted  transversely  across  the  cap,  which  is  then  soldered  to  the 
removable  section  of  the  crown.  Fig.  580  shows  the  section  of  the 
crown  in  position. 

Case  of  Dr.  Alexander's. — Fig.  581  illustrates  a  bridge  made 
by  Dr.  C.  L.  Alexander,  in  which  dovetail  slides  are  placed  on  the 
sides  of  the  crowns. 

In  either  of  these  forms  gutta-percha  can  be  used  to  securely 
attach  the  bridge  so  that  it  shall  be  detachable  only  by  the  dentist. 

An  advantage  possessed  by  these  styles  of  bridge-work  is  the 
facility  they  afford  for  the  ready  utilization  of  irregular  teeth  as 


Fig.  581. 


abutments,  no  matter  how  much  they  converge  or  diverge,  or 
lean  in  or  out  of  the  line  of  the  arch. 

Dr.  Litch's  Method. — Dr.  W.  F.  Litch's  .method  of  construct- 
ing detachable  bridge-work  consists  in  forming  a  shell  anchorage 
over  posts  permanently  fixed  in  cuspid  roots,  and  anchoring  the 
ends  of  the  bridge  with  bars  in  slots  formed  in  natural  or  artificial 
crowns. 

Figs.  582,  583,  and  584  illustrate  a  bridge  similar  to  the  one 
illustrated  in  Fig.  367  (page  196)  with  this  style  of  attachment 
applied.  The  anchorage  for  the  cuspids  is  constructed  as  follows : 
The  root  is  first  capped  and  pivoted  as  for  a  collar  crown.  On  the 
palatal  portion  of  the  collar  is  soldered  a  flange  (A,  Fig.  585) 
made  of  gold,  No.  16  gage,  beveled  off  to  the  upper  edge  of  the 
collar  under  the  free  edge  of  the  gum,  the  object  being  to  give  a 
larger  surface  to  the  top  of  the  cap.  On  this  cap,  which  covers 
the  end  of  the  root,  the  anchorage  post  B,  which  is  formed  of 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


30; 


iridio-platimnn  wire,  jNTo.  9  gage,  is  soldered,  over  and  back  of  the 
pin  (C)  which  enters  the  root-canal,  so  as  to  allow  room  for  the 
porcelain  front  D.     The  porcelain  front  is  ground  in  proper  posi- 


Fig.  582. 


Fig.  583. 


tion  on  this  cap,  backed,  attached  with  resin  and  wax,  and  re- 
moved with  the  cap.     The  cap  is  next  invested  in  plaster  to  the 


Fig.  584. 


edge  of  the  collar,  and  a  little  plaster  is  placed  on  the  labial  aspect 
of  the  porcelain  front  in  the  form  of  a  matrix,  so  as  to  allow  the 
porcelain  to  be  removed  and  replaced.     A  piece  of  heavy  iridio- 


308  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK . 

platinum  plate  (E),  about  Xo.  20  gage,  is  then  shaped  into  the 
form  of  a  half -ring,  with  the  ends  of  the  plate  against  the  backing 
of  the  porcelain  front,  and  of  sufficient  size  to  rest  on  the  flanged 
edge  of  the  cap  when  completed.  On  the  outside  of  this  half -ring 
is  fitted  and  soldered  a  thin  strip  of  gold  (F)  of  Xo.  28  gage,  which 
will  cover  the  half-ring  and  extend  beyond  its  cervical  margin, 
slightly  overlapping  the  flange  of  the  collar  (G).  This  forms 
a  brace  or  edge  on  the  anchorage  cap  as  it  rests  on  the  root-cap. 
The  half-ring  is  then  fitted  to  the  tooth,  attached  with  wax,  and 
removed  with  the  tooth  out  of  the  plaster  matrix  from  the  root- 
cap,  invested,  and  securely  soldered  on  the  inside  to  the  backing 
of  the  tooth.  The  tooth  and  half-ring  are  then  adjusted  to  the 
root-cap,  over  the  post  of  which  the  ring  must  slide  easily  (Fig. 
586).  To  this  ring  the  bridge  is  soldered  the  same  as  to  a  crown. 
When  the  bridge  is  inserted,  the  cap  for  the  root,  with 
Fig.  586.  the  post,  is  first  cemented  on  with  oxyphosphate. 
After  the  cement  has  set,  the  anchorage  ring  is  filled 
with  more  cement  and  pressed  into  position  upon  the 
cap  over  the  anchorage  post.  The  surface  of  the 
cement  (H,  Fig.  585)  can  be  protected  by  a  metallic 
tilling. 

This  form  of  attachment  permits  the  bridge  to  be 
easily  removed  by  affording  access  to  the  cement 
around  the  pin.  The  bar  ends  of  the  bridge  are 
anchored  in  the  crowns  with  gold  or  amalgam  fillings, 
which  likewise  are  not  difficult  to  remove. 

Method  of  Forming  Anchorage  Cavity  for  a  Bar 
in  a  Gold  Crown — The  anchorage  cavity  for  a  liar  in 
a  gold  molar  crown  for  use  over  a  tooth  with  a  living  pulp  is  best 
made  by  cutting  out  the  gold  to  the  form  of  the  slot  required,  and 
inserting  in  its  place  a  piece  of  platinum  plate,  about  32  to  34 
gage,  of  the  shape  of  the  walls  of  the  anchorage  cavity.  The 
crown  is  then  filled  with  investing  material,  and  the  metal  forming 
the  anchorage  cavity  soldered  to  the  crown  at  the  edges  of  the 
cavity. 

Dr.  Parr's  Detachable  Dovetail  Flange  Attachment. — Fig. 
587  illustrates  a  case  of  this  style.  The  teeth  forming  the  abut- 
ments lean  toward  each  other  posteriorly  and  anteriorly  over  the 
space  to  be  bridged,  as  shown  on  the  original  model,  Fig.  588. 
The  bridge  is  supported  by  two  shoulders  on  the  abutment  crowns, 


DETACHABLE  AXD  REMOVABLE  BRIDGE-WORK. 


309 


which  slide  into  grooves  in  the  dummies  (Fig.  589).  These  sup- 
porting shoulders  and  slots  are  made  by  shaping  two  pieces  of 
platinum  plate  to  the  form  shown  in  Fig.  590,  so  that  one  shall 
telescope  the  other.  The  inner  one  is  then  invested  on  the  outside 
surface  and  filled  in  with  gold  plate.  The  outer  piece  is  then 
filled  inside  with  investing  material,  and  gold  plate  is  flowed  over 
the  outer  surface.  The  shoulders  are  first  soldered  to  the  crowns, 
and  afterward  the  slots  are  adjusted  to  them  and  soldered  in  posi- 
tion in  the  bridge. 

Fig.  587. 


Fig.  588. 


Fig.  589. 


Fig.  590. 


Fig.  591  shows  a  bridge  constructed  with  the  attachment  just 
described  at  one  end  and  a  double-cap  attachment  at  the  other.1 

The  Griswold  System. — The  attachments  for  removable 
bridge-work  which  have  been  described,  owing  to  their  intricacy 
and  the  time  necessary  for  their  construction,  also  their  ineffective- 
ness at  times  in  retaining  a  denture  in  position,  have  been  largely 
superseded  by  manufactured  (ready-made)  attachments. 

The  Griswold  system  consists  in  the  use  of  a  manufactured  at- 
tachment by  a  special  method  which  includes  tools  for  its  appli- 
cation. 

The  attachment  consists  of  a  catch  and  socket,  termed  by  the 
manufacturer,  the  spring  and  box  respectively.      The  spring  (Fig. 


1  Case  of  Dr.  C.  L.  Alexander,  described  page  27,  Dental  Cosmos,  vol.  xxxiii. 


310 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


592)  fits  inside  the  box  (Fig.  593),  and  is  attached  to  the  crown 
and  the  box  to  the  denture,  as  illustrated  in  Fig.  594. 

The  metal  composing  the  spring  is  a  special  alloy  of  platinum, 
iridium,  and  base  metals.  It  possesses  strength  and  resiliency 
and  fuses  at  a  high  heat.  The  box  is  made  of  iridio-platinum. 
Both  alloys  are  made  into  plate,  and  the  spring  and  box  are 
formed  by  stamping  each  out  of  a  piece  of  the  plate  without 
soldering. 

The  spring  and  box  are  of  triangular  form,  with  corresponding 
corrugations  on  the  sides,  to  serve  as  a  locking  device  (3,  Fig.  592, 
and  2,  Fig.  593).  A  flange  of  the  metal  from  one  side  of  the 
spring  is  lapped  over  on  the  end  which  comes  next  to  the  gum,  for 
the  purpose  of  closing  it  (2,  Fig.  592). 

Fig.  591. 


The  box  is  slightly  flared  at  the  lower  end  (1,  Fig.  593)  to  form 
a  finder  or  guide  for  the  patient  in  setting  the  box  over  the  spring 
when  adjusting  the  denture. 

The  steps  in  the  construction  of  a  piece  of  bridge-work  with 
the  Griswold  attachments  are  as  follows : 

Make  crowns  in  the  usual  manner,  either  seamless  or  in  sec- 
tions, using  20-carat,  22-carat  gold,  or  hard-flowing  solder  in  their 
construction,  so  that  subsequent  soldering  of  the  attachments  to 
the  crowns  can  be  done  with  18-carat  solder.  Cap-crowns  with 
porcelain  fronts  on  roots  should  be  made  with  long,  substantial 
pins.  Gold  solder  applied  in  the  construction  of  all-gold  crowns 
should  not  bo   trimmed   until    the   springs   are   attached,    as   tin- 


DETACHA  BLE  A  Xl>  REMOVABLE  B III DG E-WORE. 


;;i  1 


amount  of  solder  necessary  to  be  removed  is  then  better  deter- 
mined and  soldered  seams  are  less  liable  to  be  opened  up. 

Plate  bridge-work  is  most  commonly  used  with  these  attach 
ments.  A  plate  is  accordingly  swaged,  the  crowns  placed  in  posi- 
tion in  the  month,  and  the  plate  fitted  between  them.  An  articu- 
lating impression  or  bite  is  taken  and  laid  aside.  An  impression 
is  next  taken  in  plaster  while  pressure  is  exerted  on  the  plate,  as 
described  on  page  287,  and  the  plate  and  crowns  removed  in  the 
impression.  Flow  a  thin  film  of  wax  inside  the  crowns  and  root- 
caps,  and  over  the  surface  of  each  post  and  then  run  a  plain 
plaster  model.  When  set,  remove  crowns  in  position  on  the 
model,  adjust  wax  bite,  and  make  an  articulating  model.  A 
faint  vertical  line  should  be  marked  on  the  side  of  the  crown-, 
extending  onto  the  model,  for  possible  future  reference  in  re- 
placement after  removal.      When  the  plaster  is  quite  hard,  warm 


Fig.  592. 


Fig.  594. 


the  crowns  slightly  and  remove  them,  clean  out  the  wax  with 
boiling  water,  and  replace  them  accurately. 

Next  mark  on  the  crowns  the  most  favorable  locations  for  the 
attachments.  The  angle  which  they  apparently  will  have  to  as- 
sume and  the  position  necessary  to  accommodate  the  artificial  and 
occluding  teeth  will  determine  this. 

Fig.  595  represents  what  is  called  a  soldering  jig.  It  consists 
of  a  framework  of  iron,  on  the  base  of  which  the  model  is  clamped, 
while  the  rod  and  arm  of  the  instrument  carry  the  springs  in 
parallel  lines  against  the  side  of  each  crown,  so  that  the  boxes 
which  fit  over  them  can  be  easily  adjusted  and  removed  when  at- 
tached to  the  completed  denture. 

To  set  the  model  on  the  jig,  as  shown  in  Fig.  595,  and  place 
the  springs  of  the  attachments :  First  loosen  the  clamp-screw 
marked  1,  which  fastens  the  post,  and  swing  the  rod  and  arm 
section  of  vthe  appliance  to  one  side.     Place  the  model  on  the 


312 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


base  and  clamp  it  securely  by  turning  the  thumb-screws  on  each 
side  marked  11. 

In  the  construction  and  use  of  the  jig,  the  intention  is  that 
the  large,  upright  post  and  the  elongated  rod  are  to  freely  position 
the  small  arm  and  chuck  and  the  small  arm  when  the  upright 
post  and  horizontal  rod  are  fastened  to  give  range  to  the  chuck 
that  will  carry  and  rotate  the  attachment  on  its  point. 

The  upright  post  turns  on  its  base  and  is  fixed  by  the  clamp- 
screw  marked  1.  The  rod  B  twists  and  slides  forward  and  back- 
ward, and  is  secured  by  the  screw  2.     The  smaller  section,  arm  6, 

Fir;.  595. 


can  be  tipped  at  any  angle,  forward  or  backward,  and  is  con- 
trolled by  the  screws  4  and  5.  The  chuck  13  is  connected  with 
the  arm  by  the  screws  8  and  9. 

The  different  motions  of  the  several  parts  of  the  jig  permit  the 
chuck  to  be  placed  and  then  moved  in  a  parallel  position  to  any 
part  of  the  model. 

To  set  the  arm  at  the  correct  angle  to  locate  the  soldering  chuck 
in  proper  position  against  the  sides  of  the  crowns :  First  loosen 
the  different  screws  of  the  jig  and  position  the  chuck  at  the  de- 
sired angle  against  the  sides  of  the  crowns  with  an  attachment 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK. 


slipped  on  the  point,  and  tighten  all  the  screws;  then  to  move 
the  chuck  with  an  attachment  to  the  different  crowns  it  is  only 
necessary  to  loosen  the  screws  5  and  8. 

In  adjusting  the  attachments  it  may  he  necessary  to  shorten 
them  in  accordance  with  the  bite  or  length  of  the  crowns,  but  they 
should  be  left  as  long  as  possible. 

Before  the  final  placing  of  the  springs  in  position  against  the 
crowns  they  must  be  soldered  to  reinforcing  plates.  This  is  done 
that  the  springs  may  be  more  easily  fig.  596. 

and  securely  soldered  to  the  crown-. 
The  spring  is  placed  on  the  soldering 
pliers,  which  are  shaped  to  hold  it  as 
shown  in  Fig.  596,  with  the  triangular 
edge  of  the  back  resting  on  a  piece  of 
thin  platinum  plate. 

A  piece  of  20  or  22-carat  or  hard-flowing  solder,  not  larger  than 
a  pin-head,  is  placed  on  each  side  of  the  spring,  with  a  little  flux, 
and  the  solder  is  melted  by  holding  it  in  a  Bunsen  flame.  Whit- 
ing or  wet  marble-dust  applied  inside  the  spring  will  prevent  en- 
trance of  any  of  the  solder.  A  moderate  amount  of  solder  should 
be  applied,  as  an  excess  is  liable  to  obstruct  the  adjustment  of  the 
box.  The  piece  of  platinum  plate  which  is  soldered  to  the  spring 
should  be  large  enough  to  reinforce  the  side  of  the  gold  crown  it 
will  be  placed  against  and  enable  the  crown  to  better  resist  the 
strain  exerted  on  it  in  the  insertion  and  removal  of  the  denture. 

The  springs  with  their  reinforcing  plates  are  placed  in  position 
against  the  crowns,  attached  to  them  with 
hard  wax  cement,  removed,  invested,  and 
soldered  to  the  crowns  with  18-carat  solder. 
Frequently  one  end  of  the  spring,  owing 
to  the  angle  it  has  to  assume,  stands  out 
considerably  from  the  side  of  the  crown,  as 
shown  in  Fig.  r>97.  This  space  should  be 
filled  in  during  the  soldering  with  pellets 
of  gold  foil  or  scraps  of  plate. 

The  crowns  with  the  springs  are  next  placed  in  their  respective 
positions  on  the  model.  The  springs  are  gently  closed  with  pliers 
and  the  boxes  placed  over  them.  Should  the  solder  used  to  attach 
the  springs  interfere  with  the  adjustment,  remove  a  little  of  the 
box  metal  on  each  side  of  the  slot.    The  box  should  extend  slightly 


Fig 


314  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

beyond  the  spring  toward  the  gum  and  be  cut  off  at  the  other  end 
flush  with  the  top  of  the  spring.  At  this  end  (3,  Fig.  593)  a  small 
piece  of  platinum  plate  should  be  soldered  across  the  top  of  the 
box  to  act  as  a  stay  for  the  end  of  the  spring.  The  boxes  are  next 
attached  to  the  bridge-plate  with  the  wax  cement,  removed  in 
position,  invested,  and  soldered  to  it.  The  placing  of  the  artificial 
teeth  is  done  in  the  usual  manner. 

The  cementation  of  the  crowns  is  generally  best  clone  one  at  a 
time.  The  crowns  and  denture  are  first  placed  in  position  in  the 
mouth.  The  denture  and  one  crown  are  removed,  cement  applied 
to  the  crown  and  denture,  and  the  crown  inserted.  When  the 
cement  has  set,  another  crown  or  crowns  can  be  cemented  in  a 
similar  manner. 

Fig.  598.  Fig.  599. 


Transfer   I nst rum  en i 


1,  Impression. 

_',  Box-retaining  chuck. 

To  tighten  or  loosen  the  attachment  of  the  bridge,  proportion- 
ately expand  or  contract  the  spring  that  fits  into  the  box. 

When  the  Griswold  attachment  is  applied  to  ordinary  bridge- 
work  instead  of  the  plate  form  described  above,  the  impression  is 
to  be  taken  and  the  model  and  articulating  impression  made  in  the 
usual  manner,  with  the  exception  that  plain  plaster  is  to  be  run  in 
the  caps  or  crowns,  while  plaster  and  marble-dust  are  used  for 
the  remainder  of  the  model.  After  the  attachments  are  united  to 
the  crowns,  the  artificial  teeth  or  dummies  are  set  in  position.  The 
artificial  teeth  and  boxes  are  then  cither  removed  from  the  model 
for  soldering  or  invested  on  the  model,  and  the  crowns  with  the 
springs  removed  from  it  before  sol  fieri  ng. 

The  Griswold  attachments  can  be  applied  to  advantage  to  many 
of  the  cases  which  have  been  described  in  both  removable  bridge 
and  plate  bridge-work,  alone  or  in  combination  with  some  of  the 
other  forms  of  attachment. 


DETACHABLE  AND  REMOVABLE  BRIDGE-WORK.  315 

To  Form  the  Bridge  of  Vulcanite. — When  the  springs  are 
soldered  to  the  crowns  and  the  solder  trimmed,  set  and  cement  the 
crowns  in  position  in  the  month.  To  insnre  parallel  lines  for  the 
springs  as  the  crowns  are  adjusted  with  the  cement,  insert  the 
points  of  the  transfer  instrument  (Fig.  598)  in  the  aperture  of  the 
springs  while  the  cement  is  setting.  When  the  cement  has  set 
perfectly  hard,  place  the  boxes,  with  a  little  piece  of  plate  soldered 
across  the  top  of  each  and  small  stubs  at  the  backs  for  anchorage 
in  the  vulcanite,  on  the  springs.  Xext  take  an  impression  in  plas- 
ter, which   will  remove  the  boxes  in  position.     Varnish  and  oil 

Fig.  600.  Fig.  G01. 


.Mo hk  1.,  with  I!o\  Chi  i  ;  -  P         l  I  ting 

in  Correct  Position  i  ok   Boxes.  As  Pikisi 

the  impression  and  place  ;i  box-retaining  chuck  in  each  box  (Fig. 
599),  to  locate  and  retain  the  boxes  in  exa<-t  position  on  the  model, 
which  is  next  to  be  run  in  pure  plaster.  When  the  plaster  impres- 
sion is  removed  from  the  model,  the  boxes  are  generally  also  re- 
moved from  the  chucks.  They  are  then  replaced  on  the  chucks, 
which  are  firmly  retained  in  position  by  their  shanks  in  the  plaster 
(Fig.  600).  The  artificial  teeth  are  next  arranged  in  position  on 
the  model,  the  case  waxed  up,  flasked,  packed,  and  vulcanized. 
Painting  whiting  inside  the  boxes  will  prevent  entrance  of  rubber. 
Fig.  001  shows  the  finished  denture. 


22 


CHAPTEK    XIV. 

The  Hollingsworth  System. 

construction  of  a  gold  crown  (bicuspid  or  molar) — solid  gold 
cusps— gold  crowns  (centrals,  laterals,  and  cuspids)— in- 
sertion op  a  porcelain  facing — formation  of  the  grinding 
surface  of  a  bridge  in  one  continuous  piece — facing  for 
all-gold  bridge. 

The  object  of  the  "Hollingsworth  System,"  like  some  other  so- 
called  systems  which  have  been  introduced,  is  to  systematize  and 
simplify  the  process  of  construction  of  that  style  of  crown-  and 
bridge-work  in  most  general  use.  To  this  end  the  form  of  pro- 
cedure is  concisely  outlined  and  some  special  methods  and  ap- 
pliances introduced.  The  last  mentioned  consist  of  a  set  of 
204  forms  of  solid  metallic  grinding-surfaces  of  bicuspids  and 
molars,  termed  in  -the  description  "cusp-buttons,"  for  use  in 
forming  grinding-surfaces  for  crowns  or  dummies;  thirty-six  fac- 
ings for  shaping  the  labial  surfaces  of  all-gold  bicuspid  and  molar 
dummies,  and  forty  for  labial  and  palatal  surfaces  of  all-gold 
incisors  and  cuspid  crowns.  These. collectively  are  to  be  seen  in 
the  case  illustrated  in  Fig.  602 ;  likewise  (Fig.  602  A)  some  other 
appliances  contained  in  the  set.  A  brief  description  of  the  prin- 
cipal methods  in  connection  with  the  use  of  the  appliances  is  here 
given. 

Construction  of  a  Gold  Crown  (Bicuspid  or  Molar). — Con- 
struct a  collar  to  fit  the  root  in  the  ordinary  way.  Place  the 
collar  in  the  mouth  (sec  Fig.  603),  and  cut  off  on  a  line  where 
the  adjoining  teeth  begin  to  turn  to  form  the  cusp.  (See  c,  Fig. 
603.)  Place  a  small  piece  of  wax  inside  the  collar  to  assist  in 
holding  the  cusp-button,  which  should  be  selected  to  fit  the  cir- 
cumference of  the  collar,  to  articulate  properly,  and  to  correspond 
in  shape  with  the  other  teeth.  (See  b.  Fig.  603.)  Remove  the 
button,  and  place  it  on  the  molding-plate  with  the  grinding- 
surface  up.  (See  Fig.  604.)  Place  the  small  rubber  ring  around 
316 


THE  HOLLINGSWORTH  SYSTEM. 


317 


it,  pour  a  sufficient  quantity  of  Melotte's  metal  to  nearly  fill  the 
ring  (Fig.  605).     As  soon  as  the  metal  sets,  chill  the  surface  by 


Fig.  602. 


mm 


®£ 


!MJ 


§5 


G 


-— ' 


dipping  in  water  for  a  moment,  and  then  remove  the  rubber  ring. 
When  the  heat  begins  to  return  to  the  surface,  a  quick  rap  of  the 


318  GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Fig.  602  A. 


Fig.  003. 


Fig.  605. 


Fig.  604. 


WB 


Fig.  606. 


Fig.  607. 


Fig.  608. 


cl 


Fig.  609. 


THE  HOLLINGSWORTH   SYSTEM. 


319 


die  on  the  bench  will  cause  the  cusp-button  to  drop  out  and  leave 
the  mold  ready  to  form  the  gold  cusp.  Xow  take  a  piece  of  lead, 
for  instance,  a  lead  hub,  and  with  a  hammer  drive  into  the 
Melotte-metal  die  (Fig.  606)  to  form  the  counter-die  i  Fig.  606,  d). 
Anneal  the  gold  plate,  and  start  the  swaging  process  by  coax- 
ing the  plate  into  the  die  by  hand-pressure  (Fig.  607).  using  a 
piece  of  wood  which  makes  a  depression  for  the  lend  counter- 
die  to  rest  in.  Then  place  the  counter-die  on  the  gold  plate 
(Fig.  608),  and  drive  to  a  fit.  Cut  the  surplus  metal  from  the 
hollow  cusp  with  shears  (Fig.  609),  filing  up  the  edges  when 
necessary,  and  rub  down  the  under  surface  on  a  smooth  file  until 
it  fits  the  collar  made  for  it  (Fig.  603).  "Wire  the  cusp  and  crown 
together  I  Fig.  610),  place  flux  and  solder  in  the  cap,  and  hold 

over  a   lam]")  until  soldered.     Then   finish   in  the 

usual  way. 


Fig.  010. 


Fig.  611. 


Fig.  612. 


> 


Note. — If  the  forms  of  cusp-buttons  do  not 
afford  one  which  articulates  perfectly,  the  diffi- 
culty is  easily  remedied  by  taking  the  button 
which  most  nearly  answers,  and  building  up  the 
cusps  with  Melotte's  moldine  (Fig.  611).  If  a 
collar  is  accidentally  cut  too  short,  it  can  still 
be  utilized.  Place  moldine  upon  the  molding- 
plate,  put  the  cusp-button  upon  it,  press  down  and  adjust  to 
make  up  the  deficiency  of  the  collar,  cutting  away  the  surplus 
moldine.  This  will,  of  course,  throw  the  soldering  line  a  little 
farther  up  on  the  crown  (Fig.  612). 

Solid  Gold  Cusps. — Scrap  gold  can  be  utilized  for  making  a 
solid  gold  cusp  by  casting  in  asbestos  by  the  following  method : 

After  selecting  the  desired  cusp-button,  instead  of  making  a 
mold  in  Melotte's  metal,  as  before  described,  take  a  piece  of  asbes- 
tos board  about  one  inch  square  and  one-fourth  inch  thick,  moisten 


320 


GROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


it,  and  with  a  hammer  drive  the  cusp-button  into  it,  flush  with 
the  surface  of  the  button.  (See  Fig.  613  A.)  Remove  the  but- 
ton, and  dry  the  asbestos  in  a  flame  (Fig.  613).  When  perfectly 
dry,  place  a  sufficient  quantity  of  gold  scraps  in  the  die  made  in  the 
asbestos,  and  direct  the  blowpipe  flame  upon  it  until  melted,  in- 
clining the  carbon  stick,  as  shown,  against  the  die  for  the  double 
purpose  of  confining  the  heat  and  warming  up  the  carbon  stick. 
When  the  gold  is  fused  into  a  button,  press  it  into  the  die  wTith 
the  carbon  stick  (Fig.  614).  Avoid  the  use  of 
Fig.  613.  ffux  when  working  with  asbestos. 

To  build  up  a  cusp  to  make  a  perfect  articu- 

Fig.  614. 


Fig.  613  A. 


lation,  in  this  method,  sealing-wax  must  be  used  instead  of  mold- 
ine,  as  in  swaging  the  cusp.  Warm  the  button  before  applying 
the  wax,  and  with  a  warm  instrument  shape  the  cusp  as  desired. 

Go!d  Crowns  (Centrals,  Laterals,  and  Cuspids). — Select  from 
the  forty  different  forms  in  the  set  that  which  is  most  suitable  to 
the  case  in  hand  (Fig.  615).  (The  forms  are  in  pairs,  showing 
labial  and  lingual  surfaces.)  Take  the  measurement  of  the  root 
to  lie  crowned  with  one  of  the  annealed  copper  strips,  binding  the 
strip  around  the  tooth  with  pliers  (Fig.  616,  a).  Take  this  meas- 
urement and  cut  it  through  the  center  (Fig.  616,  b),  then  bend 
the  respective  halves  over  the  lingual  and  labial  forms  selected,  at 
the  necks,  with  the  cut  ends  of  the  strips  resting  on  the  flat  of  the 
plate  (Fig.  617).  If  the  measurement  is  larger  than  the  form 
selected,  build  the  latter  up  with  moldine  until  the  space  between 
the  form  and  strip  is  filled  (Fig.  617,  b).  Avoid  getting  moldine 
on  the  approximal  surface.  Remove  the  strips,  dry  out  the 
moldine,  by  passing  through  a  flame  a  few  times,  then  place 
the   form    on    the   molding-plate   with   a    rubber   ring   around   it. 


THE  HOLLINGSWORTH  SYSTEM. 


321 


Pour  Melotte's  metal  into  the  ring  as  in  forming  the  molar  or 
bicuspid  cusp,  which  makes  a  die  of  the  two  sections,  lingual  and 
labial.  Make  a  lead  counter-die  and  proceed  as  directed  in  the 
making  of  a  molar  cusp,  swaging  both  sections  (Fig.  618).  Trim 
off  the  surplus  plate  (Fig.  619),  and  square  the  opposing  edges 
of  the.  two  sections  by  rubbing  them  over  a  dead  smooth  file. 


Fig.  615. 


Fig.  010. 


Fig.  G18. 


Fig.  619. 


Fig.  621. 


Fig.  620. 


Fig.  622. 


Bind  the  two  sections  together  with  wire  with  sufficient  solder 
and  flux  inside  (Figs.  620  and  621),  and  proceed  as  in  soldering 
an  ordinary  collar.  With  a  small  mechanical  saw  cut  off  the 
upper  portion  where  the  tooth  begins  to  slope  back  (about  the 
dotted  lines  in  Fig.  621).  This  leaves  the  crown  as  shown  in 
Fig.    622,   approximal  and  labial  views.     Fit  on  the  root.     If 


322 


CROWN-,  BRIDGE-,  AXD  PORCELAIX-WORK. 


too  small,  place  on  the  horn  of  an  anvil  and  enlarge  by  hammer- 
ing; if  too  large,  collar  the  root  in  the  same  manner  as  for  a  Rich- 
mond crown,  grinding  the  tooth  to  fit. 

To  Insert  a  Porcelain  Facing. — Make  the  gold  crown  as  de- 
scribed. Select  a  porcelain  facing  suitable  for  the  case  (Fig. 
623).  Place  the  crown  on  the  root  in  the  month,  and  with  an 
excavator  mark  on  the  face  where  the  porcelain  is  to  appear.  Re- 
move the  crown  and  saw  out,  so  that  the  facing  will  fit  loosely. 
With  a  knife  bevel  the  inner  edge  or  seat  for  the  facing  (Fig. 
624).     Grind  the  facing  to  fit  (Fig.  625).     Back  up  the  facing 


Fig.  623. 


Fig.  624. 


Fig.  625. 


Fig.  630. 


Fig.  626.  Fig.  627.  Fig.  62S.  Fig.  629.  h/L 


Fig.  631.  Fig.  632. 


with  No.  34  or  36  gage  pure  gold,  punching  holes  in  the  backing 
for  pins,  annealing  as  required  to  readily  conform  it  to  the  tooth 
(Figs.  626  and  627).  With  a  sharp  knife  cut  a  barb  on  each  side 
of  the  pins  in  the  facing,  and  press  the  barbs  against  the  backing 
(Fig.  628),  which  keeps  the  backing  in  place.  Burnish  down  the 
edges  well,  being  careful  not  to  let  the  backing  overlap  the  facing. 
Place  the  facing  in  the  space  prepared  for  it  in  the  crown  (Fig. 
629),  and  bind  them  together  (not  too  tightly)  with  wire,  wrap- 
ping the  wire  directly  over  the  facing  with  asbestos  to  prevent 
discoloration  of  the  porcelain.  Flux  and  solder  by  holding  over  a 
lamp  as  in  case  of  a  collar  (Fig.  630).      Finish  in  the  usual  way. 


THE  HOLLIXOXUOUTU  SYSTEM. 


323 


If  it  is  desired  to  use  a  platinum  pin  for  anchorage,  as,  for 
instance,  a  Logan  pin,  bend  the  pins  in  the  facing  sufficiently  to 
clamp  the  anchorage  pin,  and  insert  the  pin  through  the  gold 
crown  (Fig.  631),  finishing  as  before  described.  Fig.  632  shows 
a  finished  crown  so  made. 

Formation  of  the  Grinding=Surface  of  a  Bridge  in  One  Con  = 
tinuous  Piece.- — After  having  crowned  the  teeth  for  the  attach- 
ment of  the  bridge,  take  a  bite  in  modeling  compound,  remove  the 
compound,  place  the  crowns  in  their  impressions,  make  a  cast  of 
sand  and  plaster,  and  place  on  an  articulator;  now  put  moldine 
between  the  abutments  instead  of  wax,  and  get  the  articulation 
with  cusp-buttons  the  same  as  for  plate  teeth  (Fig.  633). 

Then,  to  remove  the  buttons  without  destroying  the  articu- 
lation, make  a  cup  by  pouring  Melotte's  metal,  as  cool  as  it  will 

Fig.  633. 


flow,  on  the  face  of  the  cusp-buttons.  Heat  the  pouring  lip  of  the 
]adle  and  use  it  to  smooth  out  the  half -congealed  metal,  much  as 
a  soldering  iron  is  used  (Fig.  634).  Then  place  a  thin  coating 
of  moldine  upon  the  molding-plate.  Remove  the  cup  from  the 
articulator  with  the  cusp-buttons  in  place  (Fig.  634,  a).  Transfer 
the  cusps  by  inverting  the  molding-plate  (Fig.  635),  and  turn  the 
cusp-buttons  out  upon  the  moldine  on  the  plate  with  the  grind- 
ing-surface  up  (Fig.  635,  a),  and  they  will  occupy  the  same  rela- 
tive positions  as  when  on  the  articulator. 

Now  place  the  large  rubber  ring  around  the  buttons  on  the 
plate,  and  proceed  to  make  a  die  with  Melotte's  metal,  as  before 
described  (Fig.  636).  When  cool,  remove  the  buttons  and  coat 
the  face  of  the  die  with  whiting.  Invert  the  die  and  raise  the 
rubber  ring  sufficiently  high  on  it,  and  make  a  counter-die  with 
the  same  metal  by  pouring  as  cool  as  possible  (Fig.  637).     This 


324 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


gives  the  male  and  female  dies  with  which  to  swage  the  con- 
tinuous grinding-surfaces.  Then  proceed  to  swage  the  gold  plate 
in  one  piece  (Fig.  638),  annealing  as  often  as  necessary.  Trim 
off  the  surplus  plate  (Fig.  638,  a),  and  place  in  position  on  the 
articulator.  Cut  the  cusps  out  on  the  buccal  face  to  avoid  show- 
ing the  gold  (Fig.  639),  grind  the  porcelain  facings  to  fit  the 
cusps,  and  back  with  gold,  No.  34  or  36  gage,  letting  it  come  to 
the  cutting-edge,  the  same  as  in  a  single  crown,  as  before  described. 


Fig.  G34. 


MELOTTES    METAL 
POURED    COLD 


Fig.  G35. 


Fig.  63G. 


Fig.  637. 


Fig.  638. 


Fig.  639. 


If  there  is  a  space  between  the  cutting-edge  and  the  porcelain, 
place  a  little  wax  in  the  joint  to  keep  out  the  plaster  investment, 
invest,  remove  the  wax  from  between  the  joints,  flux,  and  solder. 

Facings  for  Making  AlUGoId  Bridge — If  it  is  desired  to  make 
an  all-gold  bridge,  select  the  proper  facings  from  the  set,  make 
a  die  of  Melotte's  metal,  and  swage  up,  the  same  as  in  the  continu- 
ous bridge  before  described,  and  mount  gold  facings  in  place  of 
porcelain. 


CHAPTEK    XV. 

Crown-  and  Beidge-Wobk  Combined  with  Opebative  Dentistey 
in  Dental  Prosthesis. 

symmetry— cases  showing  the  results  oe  combined  operations. 

In  crown-  and  bridge-work,  artistic  skill  on  the  part  of  the 
operator  can  frequently  be  most  advantageously  displayed  in  the 
conduct  of  operations.  An  appearance  of  symmetry  should  be 
imparted  as  much  as  possible  to  the  upper  front  teeth.  The 
contour  of  the  arch,  the  labial  aspect  and  length  of  the  teeth, 
singly  and  collectively,  on  one  side  of  the  mouth  in  comparison  to 
those  on  the  other,  should  be  observed  and  studied.  That  most 
appreciable  results  are  thus  possible  of  attainment  is  demonstrated 
in  the  following  two  cases: 

Fig.  640. 


Symmetry. — In  the  case  presented  in  Fig.  640,  that  of  a  gentle- 
man of  about  sixty-two  years  of  age,  is  to  be  seen  the  irregularity 
of  the  teeth  present  and  the  unevenness  of  their  incisal  edges 
and  occluding  surfaces,  the  condition  having  arisen  from  the 
combined  effects  of  decay,  erosion,  mechanical  abrasion,  and  mal- 
occlusion. The  operations  performed  were  as  follows :  On  the 
right  side  the  second  molar  was  restored  by  filling;  the  first 
molar  and  the  bicuspid  crowned  with  gold;  the  cuspid  and  cen- 

325 


326 


CIWYX-,  BRIDGE -,  AND  PORCELAIN  WORK. 


tral  were  lengthened  with  solid  gold  tips,  each  tip  being  an- 
chored with  three  pins;  and  the  lateral  was  crowned — at  the 
request  of  the  patient — with  gold.  On  the  left  side  the  central 
was  crowned  with  a  gold  crown  with  porcelain  front,  the  cuspid 
shortened  and  filled  on  the  palatal  side,  and  the  bicuspid  crowned 
with  gold  and  the  spaces  bridged. 

Guided  by  a  line  at  right  angles  to  the  median  line  (Figs.  640 
and  641),  the  teeth  and  crowns  on  one  side  were  formed  to  cor- 
respond as  much  as  possible  in  length,  shape,  and  appearance  to 
those  on  the  other.  Those  teeth  affected  with  pyorrhea  were 
treated.  The  results  of  these  combined  operations,  conducted 
with  a  view  to  the  artistic  as  well  as  the  restorative  effect,  are 
plainly  to  be  seen  in  the  finished  case  illustrated  in  Fig.  641. 

Fig.  641. 


What  can  be  quickly  accomplished  by  judicious  trimming  and 
shaping  of  the  teeth,  in  combination  with  other  operations,  is 
well  illustrated  in  the  following  case :  The  patient's  upper  front 
teeth  presented  the  appearance  shown  in  Fig.  642.  The  right 
central  and  left  lateral  were  pulpless.  The  central  was  badly 
discolored  and  the  lateral  slightly  so.  The  central  had  been 
bleached,  but  in  a  few  years  gradually  resumed  its  former  appear- 
ance. The  other  teeth  with  living  pulps  and  light  in  color  con- 
trasted most  unfavorably.  The  incisal  edges  of  the  centrals  were 
affected  with  atrophy.  The  laterals,  especially  the  right  one,  were 
elongated  from  pyorrhea.  The  length  of  the  incisors  contrasted 
unfavorably  with  the  cuspids.  The  patient,  a  lady,  was  so  an- 
noyed at  the  appearance  of  the  teeth,  which  she  considered  a 
permanent  disfigurement,  that  she  had  positively  decided  to  have 
all  the  incisors  crowned  or  extracted  and  artificially  replaced.  A 
most  satisfactory  compromise  was  effected,  enabling  the  patient  to 


GROWN-  AND  BRIDGE-WORK  IN  DENTAL  PROSTHESIS.         327 

avoid  either  of  these  extreme  measures  by  the  performance  of  the 
following  operations :  The  pyorrhea  was  treated,  the  left  lateral 
was  bleached  and  refilled,  the  right  central  natural  crown  excised 
and  an  artificial  one  (style  described  on  page  132)  inserted,  and 
the  atrophied  incisal  edge  of  the  left  central  removed,  all  the 
incisal  ends  of  the  other  teeth  being  trimmed  to  properly  corre- 
spond in  length  and  shape.  The  improvement  effected  is  ap- 
parent in  the  illustration  of  the  finished  case,  Fig.  643. 

The  method  of  procedure  respecting  trimming  and  shaping  as 
described  in  these  cases  might  often  be  applied  advantageously  in 

Fig.  642. 


Fig.  643. 


cases  of  fracture  of  the  incisal  edge  of  the  front  teeth  too  small  to 
reliably  restore  with  porcelain. 

The  results  in  dental  prosthesis  which  can  be  accomplished 
by  a  combination  of  operations  on  the  natural  teeth  with  crown- 
and  bridge-work  commend  the  plan  strongly  to  the  experienced 
practitioner.     A  few  more  cases  are  adduced  in  illustration. 

Cases  Showing  the  Results  of  Combined  Operations. — A  case 
which  was  interesting,  owing  to  the  conditions  presented  and  the 
various  operations  connected  with  it,  is  illustrated  in  Fig.  644. 
Fig.  645  shows  the  methods  and  operations  practiced,  and  Fig. 
646  the  case  completed. 

The  upper  front  teeth  show  the  effects  of  abrasion  on  the  in- 


328 


CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 


cisal  edges  and  occluding  surfaces.  The  bicuspids  and  molars 
were  affected  with  pyorrhea  alveolaris.  The  four  incisors  and 
the  left  cuspid  were  pulpless,  and  alveolar  abscess  existed  at  the 
roots  of  three  of  the  incisors.     The  abscesses  and  root-canals  were 


Fig.  644. 


properly  treated.  Gold  collar  crowns  with  porcelain  fronts,  hav- 
ing flat  incisal  edges  which  perfectly  protected  the  porcelain 
fronts  and  slightly  opened  the  bite,  were  made  for  the  incisors  and 
left  cuspid  (Fig.  645).  The  bicuspids  and  molars  were  placed 
in   as  hygienic   a   condition   as  possible   by  treatment.      On  the 


CROIYN-  AND  BRIDGE  VORK  IN  DENTAL  PROSTHESIS. 


329 


left  side  a  dummy  bicuspid  with  a  bar  which  fitted  in  a  slot  formed 
to  receive  it  in  the  occluding  surface  of  the  second  bicuspid  was 
attached  to  the  cuspid  crown.  When  the  cuspid  crown  with 
the  dummy  bicuspid  was  cemented  in  position,  the  bar  was  an- 
chored in  the  slot  in  the  second  bicuspid  with  amalgam.  The 
cuspid  root  being  very  firm,  stability  was  thus  imparted  to  the 
natural  bicuspid,  which  was  quite  loose  because  of  absorption  of 
its  socket.  On  the  right  side  the  second  bicuspid  was  entirely 
capped  with  a  gold  seamless  crown.  On  the  anterior  side  of  this 
gold  crown  an  artificial  tooth  was  attached  as  a  dummy  first  bi- 
cuspid,  with   a  bar  extending  from   it-;  anterior  side   and  fitted 

Fig.  G-1G. 


into  a  slot  formed  in  the  incisal  surface  of  the  natural  cuspid 
crown.  From  the  posterior  side  of  the  second  bicuspid  gold 
crown  a  bar  was  extended  backward  into  the  side  of  the  molar. 
When  the  gold  crown  was  cemented  in  position  on  the  second 
bicuspid,  the  anterior  bar  was  firmly  anchored  in  the  cuspid  with 
a  gold  filling,  which  also  lengthened  the  incisal  edge,  and  the 
posterior  bar  was  fixed  in  the  molar  with  amalgam.  The  reasons 
for  this  form  of  construction  were  :  The  second  bicuspid  Avas  very 
loose  in  its  socket,  and  the  molar,  though  comparatively  more 
stable,  was  also  similarly  affected.  The  attachment  of  the  bar 
in  the  cuspid  supported  the  dummy  bicuspid  and  steadied  the 
second  bicuspid,  and  the  extension  of  the  posterior  bar  into  the 
molar  likewise  afforded  additional  support  to  the  bicuspid.  The 
pulp  of  the  molar  being  exposed,  was  devitalized,  removed,  and 


330 


CROWN-,  BRIDGE-,  AXD  PORCELAIN^YORK. 


the    canals    properly    filled.      Fig.    646    shows    the    completed 


case. 


The  lower  teeth,  in  comparison  with  the  upper,  were  but 
slightly  abraded.  The  cuspids  and  one  of  the  incisors  were  tipped 
with  gold.  The  molars  on  the  left  side  were  absent,  so  that  bridge- 
work  on  the  upper  jaw  on  that  side  between  the  bicuspid  and 
molar  would  have  been  to  no  purpose. 

In  the  case  presented  in  Fig.  647  the  operative  procedures  were 
confined  to  the  upper  jaw,  the  lower  teeth  of  the  patient  being 
in  good  condition.  The  bicuspids  and  the  first  and  second  molars 
of  both  sides  of  the  upper  jaw  had  been  lost  many  years  before, 


and  the  incisors  and  cuspids  showed  the  effects  of  extensive  abra- 
sion. The  occlusion  was  sustained  and  the  principal  part  of  mas- 
tication performed  by  the  incisors,  as  the  third  molars  had  been 
forced  backward  and  antagonized  only  very  slightly  on  one  side. 
The  patient,  a  gentleman,  had  had  a  plate  inserted,  to  the  pres- 
ence of  which  he  had  vainly  endeavored  to  accustom  his  mouth. 
The  abrasion  of  the  incisors  and  cuspids  was  of  the  rapidly  pro- 
gressive character.  These  teeth  were  contoured  with  gold  foil  to 
the  form  shown  in  Fig.  649,  and  a  wire  post  was  inserted  in  the 
right  lateral,  which  was  pulpless.  At  the  occluding  section  of 
each  filling,  the  layer  of  gold,  after  being  packed  with  the  plugger, 
was  additionally  condensed  and  hardened  with  a  Herbst  agate- 


CROWN-  AND  BRIDGE  WORK  IN  DENTAL   PROSTHESIS. 


331 


point  burnisher  to  enable  it  to  better  resist  the  aggressive  force 
of  the  lower  teeth.  The  third  molars  were  capped  and  length- 
ened with  gold  crowns,  the  lines  of  their  sides  being  made  parallel, 
to  admit  of  a  proper  adjustment  of  the  supporting  collars  for  a 
removable  plate-bridge,  by  adding  gold   on   their  external  sur- 


Fig.  648. 


Fig.  649. 


faces.  The  plate-bridge  was  employed  because  of  the  space  be- 
tween the  abutments,  which  suggested  the  idea  of  utilizing  the 
alveolus  to  assist  in  supporting  it.  A  narrow  shoulder  was  formed 
on  each  crown  to  support  the  collars.  The  attachments  to  the 
cuspids  rested  by  means  of  a  little  shoulder  on  the  occluding 
23 


.".::■' 


CROWN-,  BRIDGE;  AND  PORCELAIN-WORK. 


portions  of  the  fillings  inserted.     Fig.  648  shows  the  completed 
denture,  and  Fig.  649  an  anterior  view  of  the  same.1 

In  the  case  illustrated  in  Fig.  650,  the  patient,  a  lady,  had 
previously  worn  a  plate,  the  clasp  of  which  had  entirely  abraded 
the  sides  and  cervix  of  the  right  cuspid  of  enamel,  and  caused 
recession  of  the  margin  of  the  investing  gum.  The  decay  which 
followed  the  abrasion  extended  in  a  circle  around  the  tooth.  As 
the  patient  objected  to  crowns  of  any  kind  being  applied  to  either 
of  the  cuspids,  the  decay  was  removed  and  the  edges  of  the  cavity 
given  a  retaining  form.  A  gold  filling  was  then  introduced  in 
three  sections,  two  of  which  embraced  the  approximal  and  palatal 
sides,  while  the  third  surrounded  the  labial  Avail,  joining  the  other 

Fig.  650. 


two  sections  at  that  point,  the  three  thus  completely  encircling 
the  tooth  with  gold.  A  portion  of  the  filling  was  brought  over  the 
edges  of  the  cavity  to  better  shape  the  tooth  for  the  attachment  to 
be  applied,  and  also  to  protect  the  sides  from  future  injury.  When 
this  operation  was  completed,  the  tooth  presented  very  much  the 
appearance  of  having  had  a  close-fitting  shell  crown  applied. 
Gold  fillings  were  introduced  in  the  palatal  and  approximal  sur- 
faces of  the  left  cuspid,  to  protect  it  from  the  attachment.  Gold 
crowns  were  placed  upon  the  molars,  one  of  which,  the  left,  was 
pulpless.  The  appearance  of  the  teeth  after  these  operations  is 
shown  in  Fig.  651. 

1  Case  operated  on  in  1888.  At  the  present  time  the  author  would  sug- 
gest "Solid  Gold  Tips."  in  preference  to  fillings  for  the  front  teeth,  and  the 
application  of  the  Griswold  attachment  to  the  molars  instead  of  collars. 


CROWN-  AND  BRIDGE-WORE  IN  DENTAL  PROSTHESIS.        333 

A  plate-bridge  (Fig.  652)  was  then  constructed,  the  attachments 
for  which  were  collars  on  the  molars,  and  half-collars  or  clasps 
on  the  cuspids.  The  former  rested  on  shoulders  formed  on  the 
gold  crowns,  and  the  latter  on  the  palatal  curves  of  the  cuspids.1 

Fig.  651. 


Fig.  052. 


Fig.   653  illustrates  a  case  as  presented  for  treatment  to  Dr. 
H.  A.  Parr.     The  loss  of  the  posterior  teeth  of  the  lower  jaw 


1  Case  operated  on  in   1890. 


334 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


and  the  abrasion  of  the  anterior  teeth  had  resulted  in  the  ab- 
normal occlusion  shown.  The  incisal  edges  of  the  lower  teeth 
were  lengthened  with  gold  contour  fillings.  Gold  collar  crowns 
with  porcelain  fronts  were  placed  on  the  upper  anterior  teeth,  to 
lengthen  them  sufficiently  to  restore  the  occlusion.     The  upper 

Fig.  654. 


molars,  which  were  all  more  or  less  decayed  and  broken  down, 
were  restored  in  form  with  gold  crowns.  The  space  representing 
the  loss  of  the  left  bicuspid  was  filled  with  a  bridge-tooth  having  a 
porcelain  front,  attached  to  the  approximal  gold  crown.  In  the 
lower  jaw  a  partial  set  was  inserted  on  each  side  to  substitute  the 
lost  posterior  teeth.  Fig.  654  shows  the  appearance  of  the  case 
when  completed. 


PART  IV. 


PORCELAIN   DENTAL   ART. 


PART  IV. 

PORCELAIN  DENTAL  ART. 

By  porcelain  dental  art  is  here  meant,  not  the  well-known  pro- 
cesses by  which  porcelain  teeth  bought  from  the  manufacturer 
are  mounted  on  metal  or  vulcanite  base,  but  the  actual  working 
of  the  material  porcelain,  from  the  mixing  of  body  and  colors  to 
the  final  baking.  It  involves  the  making  by  the  dentist  of  partial 
crowns  (including  inlays),  entire  crowns,  and  even  bridges,  of 
porcelain.  It  is,  in  some  degree,  a  return  to  the  old  vogue,  when 
the  dentist  made  the  porcelain  teeth  which  he  mounted  for  his 
patients;  but  the  present  practice  is  upon  a  much  higher  plane, 
in  which  the  artistic  is  one  of  the  principal  features. 

Porcelain  dental  art,  as  here  defined,  is  an  outgrowth  largely  of 
the  common  adoption  during  late  years  of  modern  methods  of 
crown-  and  bridge-work.  At  first,  its  possibdities  not  being  clearly 
seen,  its  application  was  confined  to  a  limited  field,  its  sphere  of 
usefulness  widening  as  the  processes  became  better  understood  and 
improvement  after  improvement  was  brought  out.  Recent 
methods  in  the  manipulation  of  porcelain  leave  little  to  be  desired 
in  special  operations,  so  far  as  artistic  merit  and  real  value  are  con- 
cerned. Xor  can  the  permanency  of  these  operations  be  doubted. 
They  are  no  longer  to  be  classed  as  experimental.  They  have 
been  accepted  as  having  a  legitimate  place  in  dental  prosthesis. 
It  is  by  no  means  intended  to  be  suggested  that  the  processes  in- 
volved in  porcelain  dental  art  have  been  finally  perfected.  Im- 
provements are  quite  possible,  and  may  be  expected  as  more  and 
more  attention  is  attracted  to  this  desirable  field  of  work. 

The  successful  practice  of  porcelain  dental  art  is  not  easy,  as 
will  be  speedily  appreciated  by  those  who  enter  upon  it.  There 
is  demanded  a  technical  and  manipulative  skill  and  a  judgment 
equal  in  degree  to  those  required  in  any  other  class  of  dental 
operations,  a  fact  which  will  serve  only  to  stimulate  the  attainment 
of  perfection  in  its  methods. 

In  presenting  the  subject  we  shall  deal  first  with  the  composi- 
tion, properties,  and  methods  of  manipulating  the  porcelain  com- 
pounds at  present  in  use  in  this  line  of  work,  and  then  with  inlay-, 
crown-,  and  bridge-work. 

337 


CHAPTER    I. 

Porcelain  Compounds  or  Bodies. 

ingredients  :  their  chemical  and  physical  character— low-  and 
high-fusing  porcelain  bodies— coloring  of  porcelain  com- 
pounds—gum enamel— foundation  or  basal  body— prepara- 
tions of  porcelain  bodies— selection  of  the  color  of  the 
porcelain  body— sample  shades  —  variation  in  shade- 
spatula  and  brushes  used— preparation  of  porcelain  body 
for  use— use  of  gum  tragacanth  or  starch— application  of 
porcelain  body. 

Porcelain  Compounds  or  Bodies. 

Ingredients:  Their  Chemical  and   Physical  Character. — The 

requirements  of  this  line  of  work  have  developed  a  demand  for  a 
special  class  of  porcelain  bodies  or  compounds,  made  up  of  in- 
gredients similar  to  those  from  which  porcelain  teeth  are  made 
and  to  those  commonly  used  for  continuous-gum  work,  but  differ- 
ing from  them  in  that  they  are  lower  fusing,  are  very  finely 
ground,  and  arranged  in  various  colors.  Inlay-  and  crown-work 
body  is  composed  of  silica,  silex— the  dioxid  of  silicon;  feldspar, 
a  double  silicate  of  aluminum  and  potassium;  kaolin,  a  silicate  of 
aluminum,  decomposed  feldspar,  and  a  mineral  "flux,"  generally 
composed  of  either  flint  or  Bohemian  glass  or  their  compounds. 
Flint  glass  is  made  of  silicate  of  potash,  or  soda  and  lead  oxid; 
Bohemian  glass,  of  a  silicate  of  potash  and  lime.  Glass  of  borax 
also  is  sometimes  used  as  a  compound  in  the  "flux." 

Silica  is  highly  infusible.  It  is  used  in  a  very  small  proportion 
as  the  foundation  ingredient  of  porcelain  to  assist  in  retaining  the 
body  in  shape  during  the  fusing,  and  imparts  structural  strength. 

Feldspar  is  quite  fusible.  It  forms  a  much  larger  proportional 
part  in  the  formation  of  porcelain  than  the  other  ingredients  com- 
bined. It  serves  to  agglutinate  the  particles  of  the  more  refrac- 
tory compounds,  silica  and  kaolin,  and  imparts  a  semi-transparent 
appearance  to  the  porcelain. 
338 


PORCELAIN  COMPOUNDS  OR  BODIES.  339 

Flux  is  incorporated  to  modify  the  inf risibility  of  the  other  in- 
gredients of  the  compound.  A  flux  of  the  character  of  flint  glass 
is  much  more  effective  in  lowering  the  degree  of  fusibility  of  a 
porcelain  body  than  one  of  Bohemian  glass.  The  character  of  the 
flux  and  the  skilful  proportioning  of  it  to  the  other  ingredients 
govern  the  fusibility,  while  maintaining  the  other  characteristics 
of  a  porcelain  body. 

Lo\v=  and  High= Fusing  Porcelain  Bodies. — Porcelain  body  so 
compounded  as  to  fuse  below  the  melting-point  of  gold  and  so 
permitting  the  use  of  a  gold-foil  matrix  in  inlay-work  is  termed 
"low-fusing."  One  which  fuses  above  that  point  and  requires  the 
use  of  platinum  for  the  matrix  is  termed  "high -fusing." 

Coloring  of  Porcelain  Compounds. — Porcelain  compounds  are 
colored  to  imitate  the  shades  of  the  natural  teeth  by  thoroughly 
incorporating  certain  proportions  of  titanium  oxid  and  prepara- 
tions of  oxids  of  gold,  tin,  platinum,  iron,  cobalt,  uranium,  manga- 
nese, silver,  and  zinc.  The  exact  proportions  or  combinations  of 
these  materials  to  effect  the  desired  shades  in  the  different  prepa- 
rations of  porcelain  bodies  is  a  matter  of  knowledge  and  skill  which 
is  confined  to  the  individual  .manufacturers. 

Gum  Enamel — Gum  enamel  is  composed  of  oxid  of  gold  (pur- 
ple of  Cassius),  feldspar,  and  flux.  The  proportion  and  character 
of  the  flux  incorporated  in  the  compound  regulates  the  fusing- 
point  in  this  as  well  as  in  all  porcelain  enamels.  Gum  enamel 
gives  surface  form  to  an  artificial  gum  as  well  as  imparts  color.  It 
fuses  at  a  slightly  lower  heat  than  the  porcelain  it  is  applied  to. 
In  this  respect  the  gum  enamel  used  in  the  manufacture  of  porce- 
lain gum  teeth  and  in  the  construction  of  continuous-gum  and 
porcelain  bridge-work  differs  from  what  is  termed  pink  or  gum 
color  stain,  which  latter  is  very  finely  ground  and  fuses  at  a  com- 
paratively low  heat.  As  gum  enamel  fuses  but  imperfectly  on  the 
surface  of  platinum,  the  metal  has  to  be  first  covered  with  a  layer 
of  porcelain  body,  which  should  receive  what  is  called  the  primary 
bakes  before  the  application  of  the  gum  enamel. 

Foundation  or  Basal  Body. — Foundation  or  basal  body  is  a 
term  used  to  designate  a  preparation  of  porcelain  body  that  is  ap- 
plied first  to  form  the  base  or  foundation  of  an  inlay,  crown,  or 
bridge.  The  "Close"  porcelain  body  used  so  extensively  in  con- 
tinuous-gum work  is  an  example  of  a  foundation  body. 

The  use  of  foundation  body  is  usually  confined  to  the  foundation 


;40 


CROWN-,  BRIDGE-,  AXD  PORCELAIN  WORK. 


or  internal  portion  of  the  work,  although  certain  parts  at  times 
may  be  entirely  constructed  of  it.  Any  moderately  high-fusing 
porcelain  body  may  be  used  as  a  foundation  in  association  with 
one  fusing  at  a  lower  temperature  applied  afterward.  A  founda- 
tion body  is  generally  a  shade  darker  than  the  body  subsequently 
applied  to  accord  in  color  with  the  portion  of  the  work — the  dentin 
of  a  tooth,  for  instance — it  is  calculated  to  represent. 

Preparations  of  Porcelain  Bodies — Porcelain  body  is  pre- 
pared and  sold  in  bottles  or  jars  in  a  set  of  about  twenty-five 
different  shades,  arranged  in  a  case,  such  as  is  shown  in  Fig.  655, 


Fig.  G55. 


accompanied  by  a  set  of  samples  showing  the  colors  which  the 
various- bodies  assume  when  fused.  Some  sets  additionally  contain 
a  bottle  of  gum  enamel  and  one  of  foundation  body. 

Selection  of  the  Color  of  the  Porcelain  Body. — The  proper 
color  of  porcelain  body  should  be  selected  from  the  samples  while 
the  tooth  is  wet,  as  dryness  affects  the  shade.  In  inlay-work  for 
approximal  cavities  in  the  incisors  it  is  well  to  select  a  color  a  trifle 
lighter  than  that  of  the  natural  teeth,  as  shadows  and  the  cement 
have  a  tendency  to  darken  the  appearance  of  an  inlay.  Should 
none  of  the  colors  shown  by  the  samples  correspond  with  the  color 
wanted,  it  is  customary  to  mix  different  shades  of  the  porcelain 


PORCELAIN  COMPOUNDS  OR  BODIES.  341 

body  to  obtain  the  one  desired.  Whatever  color  is  required,  first 
ascertain  the  basal  color  and  to  this  add  the  toning  material.  For 
instance,  taking  yellow  as  the  basal  color,  a  variety  of  shades  can 
be  formed  by  the  addition  of  white,  others  still,  by  the  use  of 
blue,  and  so  on.  To  test  a  mixture  of  colors,  drop  a  small  pellet  of 
the  body,  say  about  the  size  of  an  intended  inlay,  on  a  piece  of 
blotting-paper  to  absorb  the  moisture,  and  bake  it  in  the  furnace. 
This  can  be  done  in  about  two  minutes,  and  will  positively  decide 
the  question  of  suitability.  Insufficient  fusing  will  render  the 
porcelain  a  trifle  darker  than  the  true  shade,  and  excessive  heat 
will  lighten  it. 

Sample  Shades. — Special  sample  shades  can  be  made  at  differ- 
ent times,  and  the  formula?  entered  in  a  book  and  numbered. 
Taking,  for  instance,  of  the  S.  S.  White  colors,  which  are  lettered 

Fig.  656.  Fig.  657. 


from  A  to  Z,  one  part  of  M  to  three  parts  of  G,  the  combination 
may  be  numbered  IX,  and  is  written  1  M  +  3  G  =  IX.  The 
colors  are  mixed  to  a  doughy  consistence  on  a  slab,  and  a  mold 
made  of  fusible  metal,  as  suggested  by  Dr.  V.  W.  Gilbert,  such  as 
is  shown  in  Fig.  656,  slightly  oiled,  is  pressed  down  on  the  mass 
and  removed.  The  surplus  is  then  trimmed  at  the  edges  and  the 
porcelain  baked,  resulting  in  a  sample  such  as  is  shown  in  Fig.  657. 
A  simpler  way  for  many,  though,  will  be  to  shape  the  mass  of 
porcelain  on  a  flat  piece  of  platinum  plate,  approximating  the 
form  shown  at  A  in  Fig.  657.  Flatten  one  end,  and  make  a 
hole  with  an  instrument.  Flaws  can  be  repaired  by  a  second  bak- 
ing. The  sample  shade  can  be  marked,  as  shown  in  Fig.  657,  in 
Roman  numerals  with  a  disk.  If  the  point  of  the  sample  is 
ground,  as  shown  at  C  in  Fig.  657,  the  indentation  can  be  covered 
with  oxyphosphate,  and  change  of  shade,  if  any,  will  be  exhibited. 
Variation  in   Shade. — A  difference  in  shade  between  the  re- 


342  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

*™'  gion  of  the  cervix  and  that  of  the  occluding  section,  the 
latter  being  lighter  and  more  translucent,  is  characteristic 
of  the  human  teeth.  An  imitation  of  this  variation  of 
shade  in  any  small  inlay  is  unnecessary,  but  in  the  case  of 
an  incisor  where  the  operation  involves  the  restoration  of  a 
large  part  of  the  side  of  the  tooth  including  the  incisal  edge, 
it  is  desirable.  To  effect  it  in  an  inlay,  the  same  method  is 
practiced  as  in  the  formation  of  American  artificial  teeth. 
The  first  application  of  body  to  form  the  upper  and  inner 
section  is  made  yellowish  in  shade1  to  imitate  the  dentin  of 
the  tooth,  and  the  succeeding  one,  especially  toward  the 
incisal  edge,  of  lighter  and  more  translucent  shades. 

Stability  of  Shade  in  Use.- — Stability  of  shade  in  use  is 
assured  in  high-fusing  porcelain,  while  change  is  liable  to 
occur  in  the  low-fusing  as  time  passes,  especially  should  the 
oxid  of  lead  be  used  as  an  ingredient  in  the  flux. 

Spatula  and  Brushes  Used. — A  small  tapering-pointed 
spatula  of  the  ordinary  form,  or  one  with  a  corrugated 
handle  for  the  purpose  of  vibrating  the  shank  or  handle  of 
the  appliance  supporting  the  work  during  the  application  of 
the  body,  is  the  most  suitable  (Fig.  G58).  Camel's-hair 
brushes,  such  as  artists  use  for  water  colors,  are  also  neces- 
sary. They  should  be  of  three  sizes,  the  smallest  for  carry- 
ing and  applying  the  mixed  body,  especially  small  portions 
where  an  application  or  addition  is  to  be  very  delicately 
made,  to  some  desired  spot  of  the  work;  also  for  whisking 
an  edge  or  small  corner  free  of  surplus  particles  of  the  body. 
The  medium-sized  brush  may  be  similarly  used,  or  in  the 
same  manner  as  the  large  size,  which  is  only  applied  dry  for 
brushing  the  surface  of  the  body  and  metallic  frame- 
work. 

Preparation  of  Porcelain  Body  for  Use. — In  the  pre- 
paration of  porcelain  body  for  use  absolute  cleanliness  is 
necessary,  as  the  introduction  of  the  slightest  particle  of 
foreign  matter  is  liable  to  destroy  the  appearance  of  the 
work.  The  required  quantity  of  the  powder  is  placed  on  a 
flat  or  slightly  concave  glass  or  glazed  porcelain  slab  and 

JThe  "Close"  body  when  used  for  this  purpose  should  be  ground 
finer  than  it  is  as  sold  by  the  manufacturer. 


PORCELAIS  COMPOUNDS  OR  BODIES. 


343 


Fig.  659. 


mixed  with  distilled  or,  in  its  absence,  filtered  water,  applied  from 
a  drop,  or  pipette  bottle  (Fig.  659).  The  consistence  of  the  mix- 
ture should  be  that  of  a  soft  dough.  To  obtain  this  consistence 
the  surplus  moisture  can  be  absorbed  by  light  pressure  of  the  cor- 
ner of  a  napkin  or  a  piece  of  blotting-paper  against  the  body. 
Alcohol  is  directed  instead  of  water  for  mixing  the  Jenkins  porce- 
lain, but  rapid  evaporation  is  all  there  is  to 
recommend  it,  and  this  is  an  objection  in  the  ap- 
plication of  the  body  in  some  styles  of  operations. 

Use  of  Gum  Tragacanth  or  Starch. — In  con- 
tour work  a  small  proportion  of  a  solution  of 
gum  tragacanth  or  starch  is  sometimes  added  by 
operators  to  aid  in  holding  the  particles  of  the 
body  in  form  as  the  moisture  is  evaporated. 

Application  of  Porcelain  Body. — The  porce- 
lain body  is  carried  and  positioned  on  the  work 
with  the  pointed  portion  of  the  spatula  or  with 
brushes.  In  the  application  as  thorough  a  con- 
densation or  packing  of  the  particles  as  possible 
is  desirable.  This  is  best  effected  by  placing  the 
mixed  body,  of  a  dough-like  consistence,  and  a 
little  at  a  time,  and  then  precipitating  the  parti- 
cles by  vibration.  This  is  done  by  tapping  the 
shank  or  handle  of  the  clamp  or  tray  holding  the  work  with  the 
side  of  the  spatula  or  by  drawing  over  it  the  corrugations  on  the 
handle  of  one  such  as  is  shown  in  Fig.  658.  After  each  vibration 
the  moisture  that  appears  on  the  surface  is  absorbed  with  a  small 
piece  of  blotting-paper.  The  further  details  of  the  process  will 
be  given  wmen  the  application  of  the  body  to  the  different  forms 
of  the  work  is  reached. 


Pipette  Buttle. 


CHAPTER    II. 

Furnaces. 

gas— gasoline— electric— use  of  furnaces— advantages  of  the 
electric  furnace — dental  furnace  pyrometer. 

Furnaces. — A  proper  furnace  is  essential  in  baking  porcelain. 
Small  gas,  gasoline,  or  electric  furnaces  or  ovens  specially  de- 
signed for  use  in  connection  with  crown-  and  bridge-work  opera- 
tions are  the  styles  used.  A  furnace  to  meet  all  the  requirements 
for  general  work  should  be  capable,  if  necessary,  of  generating  a 
heat  approximating  3000°  F.,  as  some  operations  in  porcelain 
may  require  a  degree  of  heat  approaching  that. 

Gas. — The  gas  furnaces  are  made  with  platinum  muffles  with 
an  open  name.  The  draft  should  always  be  sufficient  to  entirely 
consume  the  gas  and  carry  off  the  products  of  combustion.  If  this 
is  neglected,  or  if  the  furnace  is  defective,  gases  are  liable  to  pene- 
trate the  interior  of  the  muffle  and  affect  the  color  and  character 
of  the  porcelain  by  "gassing"  it,  a  condition  only  to  be  corrected 
by  substituting  new  material.  Platinum  muffles,  made  seam- 
less, are  used  in  preference  to  clay,  as  the  required  heat  can 
be  obtained  in  them  in  from  three  to  five  minutes.  A  platinum 
muffle,  although  seamless,  will  not  assure  against  the  gassing  of 
porcelain.  Fig.  660  illustrates  the  "Land  Midget  Gas  Furnace," 
operated  with  foot-bellows. 

Gasoline. — The  gasoline  furnace  is  now  being  given  preference 
over  the  gas.  The  maintenance  of  heat  production  is  dependent 
on  a  pneumatic  pump.  The  muffle  is  made  of  either  fire-clay  or 
nickel,  the  latter,  of  which  the  Brophy,  illustrated  in  Fig.  661, 
is  an  example,  being  given  the  preference. 

Electric. — In  electric  furnaces  or  ovens  the  heat  is  generated 
by  means  of  the  resistance  of  fine  platinum  wire  coiled  free  of  con- 
tact around  a  fire-clay  muffle.  The  wire  is  imbedded  as  it  encir- 
cles the  muffle  or  passed  through  small  holes  in  the  clay,  and  the 
344 


FURXACES. 


Ml 


muffle  is  inclosed  in  a  framework  of  fire-clay  or  iron  or  both 
combined.  The  electric  current  is  controlled  with  a  rheostat, 
through  which  it  is  applied  gradually  to  prevent  fusing  the 
platinum  wire.  The  handle  of  the  rheostat  should  not  be  moved 
beyond  the  first  button  for  at  least  one  minute.  After  that  it 
may  be  further  advanced  more  rapidly  on  the  other  buttons, 
until  the  required  heat  is  generated.     The  platinum  wire  around 


Fig.  GGO. 


Fig.  GG1. 


the  muffle  needs  to  be  renewed  at  intervals,  the  necessity  for 
renewal  depending  on  the  frequency  of  use,  the  amount  of  cur- 
rent, and  the  care  exercised  in  its  application.  Fig.  662  illus- 
trates a  Hammond  ^o.  2  electric  furnace,  a  size  suitable  for 
inlays  and  crowns,  and  large  enough  to  accommodate  small 
bridges. 

Use  of  Furnaces — The  gas  or  gasoline  furnace  requires  to  first 
be  well  heated  before  being;  used.    In  the  use  of  electric  furnaces, 


840 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


owing  to  the  purity  of  the  heat  generated,  this  precaution  is  not 
necessary.  The  work  may  be  safely  allowed  to  cool  gradually  in 
any  of  these  forms  of  furnaces  by  turning  off  the  heat  supply. 

Advantage  of  the  Electric  Furnace. — The  electric  furnace, 
owing  to  the  form  of  its  construction,  places  the  heat  under  perfect 
control  and  admits  of  its  regulation  by  the  pyrometer  to  a  cer- 
tainty. In  these  respects  it  possesses  advantages  over  the  other 
styles  in  use. 

The  Dental  Furnace  Pyrometer. — The  pyrometer  is  an  instru- 
ment which  indicates  the  degree  of  heat  in  the  muffle  by  a  needle 

Fig.  662. 


on  the  scale  of  the  register.  Tt  can  be  attached  to  any  style  of  fur- 
nace, but  is  commonly  used  in  connection  with  the  electric.  By 
the  aid  of  the  pyrometer  the  gradual  increase  and  exact  degree  of 
heat  is  determined  with  a  certainty  that  is  impossible  by  other 
means,  and  more  especially  by  the  eyes  in  such  small  muffles  as 
are  used  for  porcelain  inlay-  or  crown-work.  Fig.  663  illustrates 
the  Price  Pyrometer.  The  Fahrenheit  and  Centigrade  scales  are 
printed  on  the  register.  The  needle  which  registers  the  degree  of 
heat  is  operated  by  an  extremely  mild  current  of  electricity  gener- 
ated by  a  thermo-electric  couple  inserted  through  the  back  of  the 
muffle.  The  couple  is  composed  of  platinum  and  rhodium  brazed 
together.  It  is  claimed  that  the  combination  of  these  two  metals 
is  the  most  effective  for  the  purpose.    The  instrument  shows  deli- 


ITi;\'ACES. 


347 


cacy  of  construction  and  precision  in  registration.  When  the  fur- 
nace is  in  use,  if  the  door  is  opened  or  the  current  shut  off  for  a 
moment,  the  change  is  instantly  indicated  by  the  needle  on  the 
scale  of  the  register. 


Fig.  663. 


24 


CHAPTER    III. 

Fusing  of  Porcelain. 

importance  op  the  operation  of  fusing— shrinkage— baking  or 
fusing — first  bake— second  bake— final  bake— cooling,  an- 
nealing, or  tempering— difficulty  attending  the  proper 
fusion  of  small  masses  of  body— method  used  to  indicate 
point  of  fusion— advantages  of  the  pyrometer  in  indi- 
cating fusion  accurately. 

Importance  of  the  Operation  of  Fusing. — The  baking  or  fus- 
ing of  the  porcelain  body  is  one  of  the  most  important  factors  in 
porcelain  work,  as  the  result,  as  a  whole,  depends  on  its  successful 
performance. 

Density,  strength,  shade,  and  surface  gloss  and  finish  are  af- 
fected by,  and  dependent  on,  the  proper  conduct  of  fusing. 

Too  rapid  heating  or  overfusing  will  affect  the  density  and 
strength  by  causing  porosity  and  brittleness;  and  insufficient 
fusion  will  impair  its  crushing  strength  and  gloss. 

The  given  shade  of  any  porcelain  compound  depends  on  its 
fusion  at  exactly  the  heat  intended  for  that  special  preparation. 

Twenty-five  degrees  higher  or  lower  comparatively  lightens  or 
darkens  it. 

The  glaze  is  defective  if  insufficient  heat  has  been  applied,  and 
a  glass-like  appearance  is  imparted  to  the  edges  by  overfusing. 

Shrinkage — All  porcelain  compounds  shrink  in  fusing.  The 
tendency  of  the  low-fusing  is  to  ball  or  assume  a  spherical  form, 
and  of  the  high-fusing  to  contract  from  the  edges. 

These  tendencies  are  attributable  to  the  proportion  and  espe- 
cially the  character  of  the  flux  of  the  two  grades,  that  of  the  low- 
fusing  being  largely  composed  of  the  component  parts  of  glass. 
In  the  construction  of  work  most  of  the  shrinkage  occurs  in  the 
first  fusing,  in  which  it  ranges  from  nearly  40  per  cent,  in  the  low- 
to  25  per  cent,  in  the  high-fusing,  as  exhibited  in  the  chart,  page 
357. 

348 


II  sis  a  OF  PORCELAIN.  349 

The  shrinkage  of  nil  grades  of  porcelain  bodies  is  much  lessened 
by  a  thorough  condensation  or  crowding  together  of  the  particles 
as  they  are  applied  before  the  fusing. 

Baking  or  Fusing. — All  grades  of  body  require  at  least  three 
bakings  or  fusings  to  allow  the  several  shrinkages  which  occur  to 
be  corrected  and  to  effect  a  proper  vitrifaction  of  the  particles. 

The  first  fusing  is  termed  the  "biscuit  bake;"  the  first  and 
second,  "primary  bakes;"  and  the  last,  the  "final  bake." 

The  character  of  the  work  at  times  may  require  more  than  two 
primary  bakes  before  it  is  ready  for  the  final  bake. 

Requirements  in  Baking.- — In  the  first  bake,  and  likewise  in 
all  subsequent  ones,  the  work  should  be  first  slowly  heated  so  that 
all  moisture  in  the  freshly  applied  body  is  evaporated  by  degrees 
and  not  suddenly  forced  out  by  its  expansion  as  steam. 

If  such  care  is  not  taken,  particles  or  sections  of  the  body  arc 
liable  to  be  loosened  and  misplaced  or  blown  off,  thus  impairing 
the  form  of  the  work  and  engendering  porosity.  The  work  should 
be  first  set  on  a  small  fire-clay  slab,  or  in  a  tray,  and  placed  on  the 
shelf  a  little  to  one  side  of  the  muffle,  and  very  slowly  heated  to 
effect  evaporation  of  moisture,  .which  is  indicated  by  the  dry  and 
lightened  shade  of  the  body.  It  is  then  moved  to  the  center  of 
the  shelf,  heated  by  d<  grees,  and  then  introduced  into  the  muffle. 
If  an  electric  furnace  is  used,  the  work  may  be  placed  in  \\\" 
muffle  before  the  furnace  is  heated  and  the  electric  current  con- 
nected, the  voltage  gradually  increased,  and  the  work  allowed  to 
heat  up  with  the  muffle;  a  method,  however,  which  should  not  be 
attempted  with  any  other  furnace.  When  the  body  has  assumed  a 
re<  I  heat,  it  may  be  moved  quickly  to  the  center  of  the  muffle  or  a 
trifle  beyond  it,  to  a  point  which  is  generally  the  center  of  the 
greatest  amount  of  heat. 

First  Bake. — In  the  first  or  "biscuit  bake"  the  body  for  inlay- 
or  crown-work  should  be  fused  a  trifle  more  than  is  generally 
accepted  as  sufficient  in  the  corresponding  baking  of  porcelain 
teeth  or  continuous-gum  work.  The  fusing  process  should  be  so 
conducted  as  to  cause  the  maximum  shrinkage  of  the  body  and 
the  particles  to  become  solidly  united,  but  with  the  mass  still 
slightly  rough  and  glossy  on  the  surface,  though  not  glazed.  To 
accomplish  this  the  work  must  be  carefully  watched  and  in- 
stantly removed  at  the  proper  time  or  the  heat  shut  off.  If  al- 
lowed to  remain  in  the  furnace  until  the  fusing  point  is  reached, 


350  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

the  quality  and  appearance  of  the  porcelain  are  liable  to  be 
impaired  by  the  final  bake. 

The  heat  required  for  the  biscuit  bake  is  graduated  to  be  about 
100°  F.  for  the  low-  and  200°  F.  for  the  high-fusing  below 
their  respective  actual  fusing  points. 

Second  Bake. — For  the  second  bake,  the  shrinkage  which  takes 
place  in  the  first  is  compensated  by  the  application  of  additional 
body,  and  the  work  is  again  baked,  using  the  same  precautions 
in  heating  as  before. 

In  the  second  bake,  more  heat  may  be  applied  than  in  the  first. 
In  the  case  of  a  low-fusing  porcelain,  the  heat  may  be  raised  to 
within  25°  to  50°  F.  of  the  actual  fusing  point,  and  in  the  high- 
fusing  to  within  about  100°  F. 

Final  Bake — For  the  final  bake,  body  is  again  applied  at  all 
imperfect  points,  and  the  work  is  gradually  heated  until  the  actual 
fusing  point  of  the  body  is  reached.  It  is  then  allowed  to  remain 
at  that  heat  until  the  porcelain  assumes  a  smooth,  glazed  appear- 
ance, when  it  should  be  immediately  removed  or  the  heat  shut  off. 
The  time  required  to  glaze  the  porcelain  after  the  fusing  point  is 
reached  is  about  ten  to  twenty  seconds. 

Cooling  and  Annealing  or  Tempering  of  Porcelain After 

each  bake,  and  especially  the  final  one,  the  porcelain  should  be 
cooled  slowly.  This  can  be  done  by  removing  the  work  from  the 
furnace  and  inclosing  it  in  a  cooling  muffle  or  by  placing  it  under  a 
small  cover  to  protect  it  from  the  air.  A  better  plan  is  to  turn  off 
the  heat  of  the  furnace  and  allow  the  work  to  cool  in  the  muffle 
until  the  red  glow  has  disappeared  before  removing.  After  the 
last  bake  the  porcelain  is  annealed  or  tempered,  as  it  is  termed, 
by  turning  off  the  heat  of  the  furnace  and  allowing  the  work  to 
slowly  cool  in  the  muffle  of  the  furnace.  All  porcelain,  after  the 
final  baking  and  cooling,  should  be  dipped  in  water  before  hand- 
ling. 

Difficulty  Attending  the  Proper  Fusion  of  Small  Masses  of 
Porcelain  Body. — In  the  baking  of  porcelain  body  of  a  size  such 
as  is  applied  in  bridge-  or  continuous-gum  work,  the  process  of 
fusing  can  be  more  easily  watched  and  its  progress  more  surely 
determined  than  in  the  case  of  a  crown  or  inlay.  A  small  mass  of 
porcelain  body  of  the  size  of  an  inlay  is  more  quickly  affected  by 
the  heat  than  a  larger  one.  To  always  regulate  the  degree  of  heat 
by  the  eye  alone  and  also  determine  the  fusion  of  the  high- 
fusing  porcelain  body  in  such  cases  with  certainty  is  impossible. 


FUSING  OF  PORCELAIN.  351 

Removal  of  the  work  from  the  muffle  to  examine  it  instantly 
cools  such  a  small  mass,  and  several  removals  for  inspection  are 
very  injurious  to  the  porcelain. 

Method  Used  to  Indicate  Point  of  Fusion. — The  melting 
points  of  gold  and  its  alloys  with  platinum  have  been  used  to  indi- 
cate the  fusing  of  porcelain  compounds  by  first  making  experi- 
mental comparative  tests.  The  fusing  point  of  the  metal  requires 
to  be  a  few  degrees  below  that  of  the  body  for  the  biscuit  bake. 
The  gold  or  its  alloy  is  fused  in  a  globule  and  then  flattened  out 
on  an  anvil  with  a  hammer.  The  metal,  after  being  tested  with 
the  porcelain,  is  placed  upon  the  slab  with  the  inlay  or  crown. 
When  the  metal  assumes  the  spherical  form,  which  can  be  seen  by 
glancing  in  the  muffle,  it  indicates  that  the  fusion  of  the  porce- 
lain body  has  commenced.  The  globule  of  metal  can  be  used 
continuously  in  subsequent  bakings  by  flattening  it  out  each  time. 

Merits  of  a  Pyrometer. — The  introduction  of  the  use  of  a 
pyrometer  obviates  the  need  for  such  methods  as  are  described 
above.  By  the  pyrometer  the  progress  of  the  increase  of  the  heat 
and  every  variation  of  it  are  instantly  and  correctly  indicated  to  the 
operator.  Any  degree  of  heat  can  be  accurately  applied  and  regu- 
lated for  any  specified  length  of  time.  The  various  bakings  ac- 
cordingly can  be  conducted  so  as  to  result  uniformly.  Doubt  and 
uncertainty  regarding  fusing  are  removed  and  the  work  simplified. 

In  baking  with  an  electric  furnace  associated  with  a  pyrometer, 
as  soon  as  the  work  is  placed  in  position  in  the  muffle,  the  door 
is  closed  and  it  is  hidden  from  view.  The  voltage  is  then  gradu- 
ally increased  by  manipulation  of  the  rheostat,  and  the  progress  of 
the  heat  is  indicated  by  the  needle  on  the  scale  of  the  instrument. 
AVhen  the  needle  has  registered  the  required  degree  of  heat,  the 
current  is  shut  off,  the  door  of  the  furnace  opened,  and  the  work 
allowed  to  cool.  The  subsequent  and  final  bakes  can  in  like 
manner  be  given  without  variation  from  the  proper  degree  of  heat 
and  time  required  for  them,  without  once  opening  the  muffle  for 
the  purpose  of  examination.  Chilling  of  the  work,  irritation  of 
the  eyes  by  the  glare  and  heat  of  the  muffle  through  opening  it  for 
examinations,  and  loss  of  time  are  consequently  avoided.  Irregu- 
larity in  the  application  of  the  degree  of  heat  in  the  fusion  of  the 
body  of  porcelain  work  is  the  direct  cause  of  a  large  percentage  of 
failures.  Improper  conduct  of  a  primary  bake  cannot  be  entirely 
remedied  by  subsequent  fusings,  and  the  final  bake  may  destroy 


352  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

the  previous  part  of  the  work.  The  best  results  respecting 
strength,  appearance,  and  shade  in  the  use  of  any  particular  porce- 
lain compound  can  only  be  obtained  by  fusing  it  at  the  degree  of 
heat  specially  designated  for  it.  In  view  of  the  facts  presented, 
the  introduction  of  the  pyrometer,  especially  in  the  use  of  high- 
fusing  porcelain,  is  an  important  innovation. 


CHAPTER    IV. 

Staining  of  Porcelain. 

character  and  purpose  of  mineral  stains— use  of  the  colors 
—application— gradation  of  shades — fusing. 

Character  and   Purpose  of   Mineral   Stains Mineral  stains 

are  porcelain  enamels  colored  with  oxids  of  the  metals,  very 
finely  ground,  and  fusing  at  a  low  heat.  They  are  applied  to 
reproduce  the  effect  of  conditions  found  in  nature;  as,  for  in- 
stance, staining  of  edges  and  cusps  to  simulate  the  wear  through 
mastication;  of  the  fissures  of  bicuspids  and  molars  to  represent  the 
discolorations  which  appear  in  these  places  in  the  natural  teeth; 
producing  variations  in  color,  such  as  the  darker  shade  of  cuspids 
when  compared  with  centrals  or  of  the  cervical  surface  with  the 
incisal  edge  or  occlusal  surface;  the  white  specks  often  noticeable 
in  the  natural  teeth;  and,  in  general,  the  modifying  or  darkening 
of  a  single  tooth  or  a  number  of  teeth. 

The  Brewster  mineral  stains  are  mixed  with  oil,  and  those  of 
The  S.  S.  White  Dental  Mfg.  Co.  with  water.  The  colors  of  The 
S.  S.  White  Dental  Mfg.  Co.  are  seven  in  number — brown. 
yellow,  gray,  blue,  white,  and  green,  and  pink  for  gum  shading. 
By  combining  them  one  can  get  a  great  variety  of  shades.  Mix- 
ing brings  out  the  colors  very  nearly  as  they  will  appear  when 
fired,  the  firing  merely  intensifying  and  fixing  them.  By  the 
skilful  application  of  these  stains  artistic  effects  can  be  produced. 
Their  successful  use,  however,  requires  practice  and  care.  More 
than  a  little  experimental  work  is  necessary,  and  tests  on  a  dis- 
carded tooth  should  first  be  made,  as  it  takes  but  a  few  minutes. 

Use  of  the  Colors. — In  applying  the  stains,  if  the  tone  of  the 
tooth  is  yellow,  the  addition  of  brown  will  at  first  darken  the 
yellow,  then,  as  more  and  more  is  added,  bring  out  a  more  and 
more  decided  brown. 

If  the  tone  is  blue  or  gray,  brown  at  first  merely  deepens  it, 
but  on  the  addition  of  a  considerable  quantity  produces  a  decided 
brown. 

353 


354  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

The  white  spots  frequently  seen  in  the  enamel  of  natural  teeth 
can  be  imitated  by  applying  a  thin  layer  of  white,  stippling,  and 
firing  in. 

For  representing  the  wear  of  mastication  the  teeth  are  ground 
and  the  cutting-edges  and  fissures  stained  brown. 

Defects  in  the  enamel,  as  pits  or  grooves,  can  be  imitated  by 
drilling  out,— use  a  diamond  drill  for  this, — applying  the  color, 
and  firing. 

A  combination  of  the  green  with  the  brown  will  give  a  natural- 
looking  stain  similar  to  that  found  upon  the  teeth  of  inveterate 
"smokers." 

Inlays  or  crowns,  the  color  of  which  fails  to  match  their  sur- 
roundings, can  be  quickly  brought  to  the  desired  shade  by  the 
addition  of  the  proper  color  and  firing. 

Natural  "cutting-edge"  effects  may  be  obtained  by  using  either 
gray  or  blue  as  an  underglaze  color,  i.  e.,  after  applying  and  firing 
the  color,  cover  the  same  with  a  colorless  medium-  or  high-fusing 
porcelain  and  again  fire. 

The  pink  or  gum  color  will  be  found  useful  in  covering  plati- 
num bands  which  are  exposed  below  the  gum  line,  also  in  coloring 
that  portion  of  an  inlay  which  lies  under  the  cervical  margin,  and 
in  disguising  the  necks  of  porcelain  teeth  whose  cervical  margin  is 
above  or  below  the  adjoining  teeth. 

Application. — The  enamel  stains  are  applied  with  a  small  brush 
and  evenly  distributed  over  a  given  surface  with  a  stippling  brush, 
both  of  which  accompany  the  outfit  of  stains.  The  colors  are  in- 
tended for  use  on  perfectly  fused  surfaces,  but  they  may  also  be 
applied  after  the  biscuit  bake  or  primary  bake,  and  the  tint  then 
modified  by  the  translucency  of  the  additional  body,  which  will 
be  distributed  over  the  part  for  the  subsequent  bakes. 

A  change  of  shade  of  only  a  part  of  a  facing  toward  the  incisal 
edge  in  the  construction  of  a  crown  or  dummy  may  be  effected 
in  this  way  by  the  application  of  the  stain  to  the  palatal  side  of  the 
porcelain. 

Gradation  of  Shade — Gradation  of  shade  is  controlled  by 
varying  the  thickness  when  laying  on  the  color.  This  can  be 
effected  by  placing  on  the  color  with  the  small  brush  and  then 
graduating  it  with  the  stippling  brush.  It  can  also  be  done  by 
wiping  the  color  off  with  the  fingers.  To  effect  gradation  of  shade, 
for  instance,  around  the  neck  of  a  tooth  with  perfect  accuracy, 


STAINING  OF  PORCELAIN.  355 

the  color  can  be  first  evenly  applied  to  the  part  and  given  a 
primary  bake.  The  surplus  color  toward  the  edge  is  then  re- 
moved with  a  sandpaper  disk,  making  it  gradually  lighter,  when 
the  final  bake  is  given  and  the  enamel  glazed. 

Fusing. — In  fusing  the  applied  mineral  stains,  place  porcelain 
teeth  with  the  pins  downward  on  a  fire-clay  slab,  or,  if  a  crown,  set 
it  upright.  Apply  the  heat  gradually  until  it  reaches  a  dull  red, 
and  hold  it  at  that  point  for  two  or  three  minutes.  Cool  gradually. 
These  colors,  though  glazing  at  a  low  heat,  will  well  retain  their 
shade  when  fused  on  or  with  porcelain  at  a  much  higher  point. 


CHAPTER    V. 

Character  and  Suitability  of  Low-  and  High-Fusing  Porce- 
lains for  Inlay-  and  Crown-Work. 

requirements— comparative    merits— tests    of    dental    porce- 
lains—suitable application  of  each  grade. 

Requirements.- — The  value  of  the  respective  grades  of  porce- 
lain for  the  work  in  hand  is  governed  by  their  imitation  of  tooth- 
substance,  density,  strength,  permanence  of  structure,  retention  of 
form  in  the  process  of  fusing,  close  adaptation  of  the  finished  inlay 
to  the  margin  of  the  cavity,  and  lastly, — a  most  important  fac- 
tor,— practicability  in  application.  Porcelain  dense  and  strong 
enough  for  use  as  an  ordinary  labial  inlay  might  be  deficient 
in  the  properties  requisite  to  the  formation  of,  for  instance,  an 
incisal  edge  for  an  incisor  tooth,  which  would  demand  the  greatest 
possible  strength  that  can  be  obtained  in  porcelain.  Neither 
would  porcelain  body  designed  to  form  an  incisal  edge,  approach- 
ing in  character  body  such  as  composes  porcelain  teeth — the  pul- 
verized porcelain  tooth  used  at  times  by  some  for  the  purpose 
requiring  a  most  intense  heat  to  fuse  it — be  as  suitable,  even 
judged  from  a  practical  standpoint,  for  forming  an  inlay. 

Comparative  Merits. — The  comparative  merits  of  low-  and 
high-fusing  porcelain  for  the  work  in  hand  is  a  matter  as  to  which 
considerable  difference  of  opinion  prevails.  This  is  probably 
attributable  to  the  fact  that  the  knowledge  or  experience  of  many 
operators  is  confined  in  a  measure  to  the  grade  they  have  in  use 
and  the  methods  connected  with  that  use.  Skilful  proportionment 
and  preparation  of  the  various  ingredients  of  a  porcelain  body 
realize  the  best  results  in  the  fused  porcelain.  In  this  way  the 
fusing  point  of  some  preparations  may  be  lowered,  yet  their  com- 
parative qualities  be  maintained.  The  following  gives  the  fusing 
point,  percentage  of  shrinkage,  and  crushing  strength  as  recently 
determined  by  Dr.  D.  O.  M.  LeCron  in  a  series  of  experiments 
with  a  number  of  the  best-known  dental  porcelains.  In  studying 
the  results  of  these  tests  the  resistance  or  crushing  strength 
35G 


CHARACTER  AXD  STABILITY  OF  PORCELAINS. 


35' 


should  be  considered  more  than  shrinkage,  for  while  the  latter 
complicates  the  use  comparatively,  the  former  concerns  the  relia- 
bility and  permanence  of  the  operation. 

Tests  of  Dental  Porcelains 


Fusing 
Temperature. 

Allen's    Foundation     2340°  F. 

Close's    Foundation     2288°  F. 

Consolidated  Dental   Mfg.  Co.'s  Founda- 
tion      2200°  F. 

The  S.  S.  White  Dental  Mfg.  Co.'s  High- 
Fusing  Inlay    2254°  F. 

Brewster's   Foundation    2218°  F. 

Consolidated  Inlay   2138°  F. 

Whiteley's     2138°  F. 

Brewster's  Enamel    2084°  F. 

Ash's  High-Fusing   2012°  F. 

Jenkins' 1580°  F. 


Crushing 

Strength, 

Percentages 

Pounds 

of  Shrinkage. 

Per  Sq.  In 

22* 

20,950 

213 

45,640 

2H 


30.390 


23i 

32,205 

23| 

20,320 

31 

15,080 

31 

16.000 

33 

22.990 

34f 

22.810 

38$ 

28,305 

Suitable  Application  of  Each  Grade — According  to  the  con- 
ditions discussed,  in  the  present  development  of  the  art  the  use 
of  low-fusing  porcelain  is  best  confined  to  inlays  at  labial  and 
approximal  surfaces.  It  is  inferior  to  a  moderately  high-fusing 
porcelain  for  inlays  at  or  extending  to  the  occluding  surface  or 
incisal  edge,  and  for  porcelain  and  platinum  crown-work,  where  a 
porcelain  as  nearly  analogous  in  structure  to  the  usual  artificial 
tooth  in  part  or  whole  is  required. 


CHAPTER    VI. 

Porcelain  Inlays. 

the  earlier  methods — modern  inlays  and  their  merits — in- 
struments and  materials  used  in  the  adaptation  of 
matrices— preparation  of  cavities— formation  of  gold  ma- 
trices for  the  low-fusing  porcelains — platinum  matrices — 
to  facilitate  the  shaping  of  a  matrix — molds  and  dies  for— 
oxyphosphate  impressions— process  of  shaping  a  matrix  by 
a  mold  or  die— discussion  of  proportion  of  displacement  by 
a  matrix— removal  of  a  matrix  :  gold— platinum — methods  to 
aid  removal— investing  the  matrix— application  of  porce- 
lain body — the  jenkins  low-fusing  :  application,  fusing— use 
of  electric  furnace  in  baking  low-fusing  porcelain— esti- 
mated degree  of  heat— high-fusing  porcelain:  application 
— first  bake — second  bake — final  bake— comparative  heat 
of  the  final  bake— removal  of  a  foil  matrix — preparation 
for  cementation — methods  of  etching  with  acid  or  a 
diamond — use  of  a  lens — to  aid  adjustment  in  cementation 
— requirements :  effect  on  color— operation  of  cementa- 
TION. 

Porcelain  Inlays. 

The  Earlier  Methods — The  first  operations  in  porcelain  inlays 
or  fillings  consisted  in  shaping  pieces  of  porcelain  as  nearly  as 
might  be  to  the  form  of  the  prepared  cavity,  into  which  they  were 
then  cemented.  These  inlays  were  cut  from  porcelain  teeth,  which 
were  selected  to  match  the  natural  teeth  into  which  the  inlays 
were  to  be  inserted.  Various  forms  of  inlays  were  then  put  upon 
the  market  by  the  manufacturers  to  meet  the  needs  of  this  class 
of  work,  which,  however,  never  attained  any  special  prominence. 
A  little  later,  slightly  tapering  round  rods  of  porcelain  were  sup- 
plied for  filling  labial  cavities  in  front  teeth.  The  cavity  was 
made  perfectly  round,  to  fit  the  end  of  a  rod  corresponding  in 
size,  which  was  fitted  tightly,  cut  off,  cemented  in  place,  and 
when  the  cement  had  set  was  trimmed  evenly  with  the  surface  of 
358 


PORCELAIN  INLAYS.  359 

the  enamel  of  the  tooth.  This  latter  method  is  still  employed, 
being  especially  adapted  to  very  small  cavities  on  the  labial  sur- 
faces. 

Then  we  had  glass  inlays,  of  which  a  number  were  brought  be- 
fore the  profession,  but  they  failed  to  show  the  permanent  value 
requisite,  mainly  because  the  inlays,  besides  lacking  the  necessary 
strength,  showed  a  decided  tendency  to  discolor  in  actual  service. 
They  were,  nevertheless,  an  important  step  in  the  progression 
which  led  up  to  the  modern  porcelain  inlay. 

Modern  Inlays  and  their  Merits. — The  porcelain  inlay  as  now 
used  is  a  dental  porcelain  fused  in  a  carefully  made  matrix  of  the 
cavity  to  be  filled,  of  the  exact  form  and  size  required.  The  two 
grades  of  porcelain  for  inlay-work  are  the  low-fusing,  for  which 
a  gold  matrix  is  used,  and  the  high-fusing,  requiring  a  matrix  of 
platinum.  Their  respective  merits  for  inlay-work  have  been  much 
discussed,  without  deciding  the  difference  of  opinion  concerning 
them.  The  characteristics  of  both  and  the  methods  of  their 
manipulation  and  their  application  to  the  various  operations  will 
be  impartially  presented. 

Properly  made  and  inserted,  porcelain  inlays  afford  the  very 
decided  advantage  of  restoring  lost  tooth-structure  not  only  in 
substance,  but  in  appearance.  Porcelain  inlays  are  used  princi- 
pally on  the  labial,  buccal,  and  approximal  surfaces  of  teeth  from 
bicuspid  to  bicuspid.  They  are  also  used  on  the  occlusal  sur- 
faces of  bicuspids  and  upon  the  anterior  approximal  sides  of  molars 
where  the  tooth  immediately  in  front  is  missing.  In  combination 
with  the  cement  used  to  fix  them  they  add  strength  to  a  frail 
tooth  and  prevent  thermal  shock  in  sensitive  cavities. 

The  first  requirement  in  a  porcelain  inlay  is  that  it  shall  ac- 
curately conform  to  the  shape  of  the  cavity,  with  an  absolute  fit 
of  the  orifice  or  of  the  orifice  and  side-walls.  The  cement  with 
which  it  is  luted  fills  in  all  parts  of  the  cavity  not  occupied  by  the 
porcelain,  including  deep  recesses  and  undercuts.  The  inlay  is 
consequently  held  in  position  by  the  adhesion  of  the  cement. 

In  cases  of  cervical  decay  extending  under  the  gum-margin, 
the  cavity  should  be  previously  packed  with  cotton  or  gutta-percha 
and  the  gum  pressed  from  its  normal  position  sufficiently  to  fully 
expose  the  edge  of  the  cavity  and  admit  of  the  perfect  adaptation 
of  the  matrix.  In  approximal  cavities  the  teeth  should  be  pre- 
viously separated  well  apart — more  so,  as  a  rule,  than  for  gold 


360 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


Fig.  GG6. 


filling-operations — so  that  the  adaptation  of  the  matrix  shall  not  be 
obstructed  or  its  removal  interfered  with  in  the  slightest  degree. 
When  the  decay  extends  further  under  the  gum 
than  it  is  desirable  to  extend  the  inlay,  the  cervical  sec- 
tion of  the  cavity  may  be  first  restored  with  amalgam 
(Fig.  664)  and  then  the  coronal  portion  shaped  and 
inlaid  with  porcelain. 

Instruments  and  Materials  Used  in  the  Adapta= 
tion  of  Matrices. — Small-pointed  and  specially-shaped 
burnishers  are  necessary  for  the  proper  adaptation  of 
matrices  to  cavities.  Fig.  665  illustrates  a  set  devised 
by  Dr.  LeCron.  ISTos.  1  and  11  are  for  general  use; 
NTos.  2,  3,  and  4  for  the  interior  of  cavities;  Nos.  5,  6, 
7,  8,  9,  and  10  for  the  margin  of  the  cavity  and  the 
surface  of  the  tooth  combined.  Fig.  666  shows  round- 
pointed  tweezers  for  carrying  pellets  of  spunk  or  cot- 
ton used  to  compress  the  foil  for  the 
o:h  matrix  into  the  cavity  of  the  tooth. 
They  may  also  be  used  as  a  burnisher. 


Fig.  604. 


Preparation  of  Cavities. — Cavi- 
ties for  porcelain  inlays  are  to  be  ex- 
cavated more  as  for  plastic  work  than 
for  gold,  and  without  undercuts.  The  effort  should 
be  to  give  a  cup-shaped  formation  with  the  orifice  a 
little  larger  than  the  bottom,  so  that  the  matrix  of 
gold  or  platinum  when  adapted  to  the  cavity  can  be 
removed  without  disturbing  its  shape.  This  ideal 
form  is  not  to  be  obtained  by  excessive  removal  of  the 
walls  or  enamel.  Unnecessary  cutting  away  of  tooth- 
substance  is  to  be  avoided.  When  the  decay  has  pro- 
ceeded in  such  way  as  to  form  deep  recesses,  it  is  not 
desirable  nor  necessary  to  cut  away  the  tooth  to  make 
the  ideal  cavity  form  include  them.  After  removing 
the  carious  portions  from  such  recesses,  they  can  be 
filled  with  cement  so  that  the  cup-shaped  form  for  the 
matrix  shall  include  only  the  main  cavity,  the  cement 
where  it  joins  the  main  cavity  being  dressed  to  con- 
form to  the  proper  contour.  The  exception  to  this 
rule  is  where  a  bar  or  horn-like  formation  of  the  porce- 


PORCELAIN  IX LA)  8. 


361 


lain  is  made  at  some  point  as  an  anchorage  to  an  inlay  which  in- 
volves restoration  of  the.  contour  of  the  working  surface  of  the 
tooth,  as  of  an  incisal  edge.  The  orifice  of  the  cavity  should  be 
given  a  slightly  oval  or  oblong  form,  with  one  end  or  side  differ- 
ing somewhat  in  shape  from  the  others,  to  define  the  exact  posi- 
tion the  inlay  is  to  occupy  when  inserted  in  the  cavity.  The  mar- 
gins should  be  trimmed  evenly  and  the  side-walls  inclined  at 
nearly  a  right  angle  to  the  line  of  the  enamel  surface,  especially 
at  a  point  where  the  force  of  mastication  is  to  be  withstood.  The 
surrounding  edge  of  the  enamel  should  be  sharp  and  well  defined. 


Fig.  GG5. 


It  is  well  to  polish  around  the  margins  inside  the  cavity  with  soft 
iron  burs  charged  with  diamond  dust,  or  with  points  of  Arkansas 
stone  kept  wet  during  the  polishing.     A  set  of  forms  such  as  are 


Fig.  607, 


illustrated  in  Fig.   66V   are  suitable  for  the  purpose.      The 

use  of  sandpaper  disks  or  strips  across  the  surface  of  the 

J     enamel  should  be  avoided,  as  it  is  apt  to  make  a  coarse  joint. 

Figs.  663,  669,  670,  and  671  illustrate  teeth  with  prepared 


362 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


cavities  and  their  inlays  of  the  classes  commonly  involved  in  the 
practice  of  porcelain  work. 

Fig.  672  outlines,  in  section,  the  preparation  of  an  ordinary 
cervical  cavity.  The  line  A,  A  represents  the  prepared  cavity; 
B,B  the  point  where  the  undercut — though  this  is  generally  better 
omitted — may  be  made  Avhen  the  porcelain  is  ready  for  insertion. 
C,  C  is  the  gold  or  platinum  matrix.  Such  cavities  require  to  be 
moderately  deep,  in  order  that  the  inlay  shall  be  of  sufficient  thick- 

Fig.  668. 


Fig.  669. 


Fig.  670. 


Fig.  671. 


ness  to  overcome  the  effect  of  the  cement,  which  would  otherwise 
modify  the  shade,  owing  to  the  translucency  of  the  porcelain.     A 


PORCELAIN  INLAYS. 


363 


cavity  of  this  character,  if  not  located  very  close  to  the  gum- 
margin,  being  one  of  the  most  simple,  is  generally  the  best  to 
begin  practical  work  on. 

Fig.  672. 
C  C, 


Fig.  673  represents  a  typical  cavity  in  the  approximal  side  of 
an  incisor.  The  dark  portion,  A,  in  the  sectional  view,  represents 
a  recess  in  the  cavity  made  necessary  by  extension  FlG  673 
of  the  decay  in  that  direction,  which  recess  must  be 
filled  with  cement  to  give  proper  form  to  the  matrix. 
In  the  case  of  approximal  cavities,  ample  space  is  re- 
quired for  the  proper  manipulation  of  the  matrix  and 
the  insertion  of  the  porcelain  filling.  The  necessary 
room  must  be  obtained  by  preparatory  wedging  or 
by  the  use  of  a  separator,  or  by  combining  both 
methods.  There  must  be  sufficient  space  to  permit  the  matrix, 
after  it  has  been  perfectly  conformed  to  the  cavity,  to  be  lifted 
out  without  disturbing  its  form  in  the  least,  and  also  to  allow 
the  porcelain  to  be  freely  inserted. 

In  the  upper  incisors,  when  a  portion  of  the  palatal  wall  can 
properly  be  removed,  as  shown  at  A,  Fig.  669,  less  space  is  re- 
quired, and  removal  of  the  matrix  and  insertion  of  the  inlay 
are  considerably  facilitated'.  Cavities  in  bicuspids  and  molars, 
such  as  are  illustrated  in  Figs.  670  and  671,  involving  the  ap- 
proximal and  grinding-surfaces,  usually  permit  the  matrix  to  be 
more  easily  removed  than  when  only  an  approximal  surface  is 
involved. 

Formation  of  Gold  Matrices  for  the  Lo\v=Fusing  Porcelains. 
— Rolled  gold  No.  30  is  used  for  ordinary  cavities  and  No.  40  for 

25 


364 


CltOWX-,  BRIDGE-,  AND  PORCELAIN -WORK. 


those  which  are  extremely  large  or  complicated  in  shape.  The  foil 
should  be  cut  round  or  oval,  large  enough  to  cover  the  walls  of 
the  cavity  and  extend  over  the  adjacent  surface  of  enamel  one- 
fourth  of  an  inch,  more  or  less,  according  to  the  location,  character, 
and  size  of  the  cavity,  to  permit  it  to  be  immovably  held  in  posi- 
tion during  its  adaptation.  The  surplus  foil,  when  shaped  to  the 
contour  of  the  tooth  around  the  cavity,  serves  to  outline  the  con- 
tour to  be  given  the  inlay  when  the  porcelain  body  is  inserted  in 
the  matrix.  The  foil  is  placed  over  the  cavity,  the  edges  of  which 
are  denned,  and  is  first  brought  gently  down  into  the  center  of 
cavity  with  a  bit  of  spunk  or  a  pellet  of  cotton  held  in  a  pair  of 
tweezers  (Fig.  666),  or  when  necessary  by  a  ball  burnisher,  as 
No.  2  of  the  set  illustrated  in  Fig.  665,  and  then  against  the 
walls.    Remove  the  spunk,  see  if  the  adjustment  of  the  foil  to  the 


Fig.  G74. 


v- , ' 

G  G  represents  line  of  gum- 
margin  ;  F,  line  of  foil 
under  the  gum. 

cavity  is  satisfactory,  then  replace  the  spunk,  holding  it  in  place 
with  the  left  hand,  by  pressing  in  the  center  with  a  ball  burnisher. 
Next,  with  another  piece  of  spunk  held  in  tweezers  in  the  right 
hand,  bring  down  the  foil  over  the  edges  and  on  the  surface  of  the 
enamel  around  the  cavity,  and  burnish  it  with  a  burnisher,  such  as 
No.  1  or  No.  11  in  Fig.  665.  In  the  adaptation  of  the  foil  to  the 
cavity,  and  especially  for  holding  it  in  position  in  the  center  while 
the  marginal  section  is  being  manipulated,  the  author  has  found 
that  a  wisp  of  cotton,  tightly  twisted  around  an  old-fashioned,  long- 
handled  cavity  bur,  is  very  serviceable.  The  ball-pointed  tweezers 
illustrated  in  Fig.  666  are  recommended  for  this  part  of  the  work. 
The  foil  should  then  be  burnished  to  the  sides  and  margins  of  the 
cavity  and  over  the  surface  of  the  tooth  to  impart  the  greatest 
possible  amount  of  rigidity  to  it  before  its  final  removal.  In  a 
mesial  cavity  of  a  superior  central  the  foil  appears  about  as  illus- 
trated in  Fig.  674,  and  in  a  cervical  one  as  shown  in  Fig.  676. 


PORCELAIN  INLAYS.  3(35 

Gold  foil  is  seldom  removed  and  annealed  during  its  adaptation. 
A  little  vaselin  may  be  applied  to  the  surface  of  the  gum,  enamel, 
and  cavity  to  prevent  adhesion  of  the  foil.  In  cases  where  the 
cavity  closely  approaches  to  or  extends  under  the  gum-margin, 
rigidity  will  be  imparted  to  the  portion  of  the  foil  placed  there 
(see  Figs.  674  and  676)  by  folding  the  edge  over  before  adapta- 
tion, as  shown  at  L  L,  in  Fig.  675.  The  foil  when  adapted  should 
be  so  positioned  that  a  slight  space  will  exist  between  the  lap-over 
edge  and  the  margin  of  the  cavity,  about  as  is  also  shown  in  Fig. 
674. 

Platinum  Matrices. — Platinum  foil  1/1000  of  an  inch  in 
thickness  is  the  gage  most  generally  used  for  the  high-fusing  porce- 
lain matrix.  To  render  the  platinum  soft  enough  for  the  purpose 
it  should  be  previously  annealed  at  a  white  heat  in  the  muffle  of  a 
gas  furnace,  or,  preferably,  on  a  piece  of  lime  in  an  electric  fur- 
nace. Annealed  by  the  latter  method  it  becomes  nearly  as  soft  and 
pliable  as  gold.  A  direct  gas  flame  is  not  suitable,  as  the  desired 
softness  cannot  be  obtained  by  that  means  and  the  platinum  be- 
comes slightly  carbonized.  The  foil  is  placed  across  the  cavity 
and  cut  large  enough  to  extend  on  each  side  a  little  more  than 
if  of  gold  foil,  so  that  it  can  be  held  securely  in  position.  In 
the  case  of  a  labial  cavity  the  platinum  is  allowed  to  extend  over 
the  surface  of  the  adjoining  teeth.  If  the  cavity  is  on  the  side  or 
at  the  incisal  edge,  the  foil  is  brought  over  on  the  labial  and 
palatal  surfaces.  The  foil  is  first  carefully  and  gently  pressed 
into  the  cavity  in  such  manner  as  not  to  tear  it,  and  the  side  por- 
tions are  then  brought  down  in  position  against  the  surface  of  the 
tooth  or  adjoining  teeth  should  the  platinum  extend  there.  While 
being  firmly  held  in  position  against  the  slightest  movement,  the 
foil  is  carefully  adapted  to  the  cavity  by  burnishing.  This  process 
is  begun  at  the  edge  of  the  cavity  with  a  circular  motion  of  the 
burnisher  around  the  margins.  As  the  platinum  sinks  into  the 
cavity  the  metal  is  gradually  brought  down  against  the  sides  and 
finally  in  the  center.  If  the  metal  was  first  pressed  down  in  the 
center,  as  gold  foil  is,  the  platinum  would  be  torn  to  an  extent  that 
would  spoil  it  as  a  matrix.  At  this  stage  of  the  formation  of  the 
matrix,  if  desirable,  the  foil  is  removed,  annealed,  and  replaced  in 
the  cavity,  reburnished  to  the  cavity  and  then  to  the  edge  and  sur- 
face of  the  enamel,  and  removed.  Before  finally  removing  the 
matrix  it  is  advisable  to  uniformly  compress  its  entire  surface  to 


366  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK . 

the  walls  of  the  cavity  and  adjacent  surface  of  the  tooth  to  remove 
any  slight  spring  or  warpage  should  such  exist.  This  is  done  by 
introducing  into  the  cavity  and  placing  over  the  surface  of  the 
tooth  pieces  of  spunk  and  pressing  uniformly  at  the  same  time 
on  the  entire  mass.  It  may  be  done  also  by  stretching  a  piece  of 
rubber-dam  tightly  over  the  foil.  The  spunk  is  first  removed  and 
then  the  foil  carefully  started  and  lifted  from  the  cavity. 

Platinum  foil  as  light  as  1/2000  of  an  inch  requires  to  be 
adapted  to  the  cavity  in  a  manner  very  similar  to  gold  foil. 

Should  either  gold  or  platinum  foil  tear  slightly  in  the  center 
of  the  cavity,  it  is  not  a  serious  matter,  as  the  porcelain  body  will 
draw  from  the  edge  in  the  first  fusing. 

Platinum  foil  has  the  advantage  that  it  can  be  adapted  to  the 
surface  of  a  tooth  under  a  gum-margin  more  easily  than  gold. 

To  Facilitate  the  Shaping  of  a  Matrix — To  facilitate  the 
shaping  of  either  a  gold  or  platinum  matrix,  the  foil  may  be  placed 
on  the  surface  of  a  piece  of  soft  fine-grained  cork,  and  with  a  hall- 
shaped  burnisher  the  center  may  be  pressed  into  the  cork  and 
given  a  cup-shaped  form  approximating  that  of  the  cavity.  A 
slit  placed  in  the  foil  at  about  the  point  A,  Fig.  669,  has  also  been 
suggested,  but  this  is  preferably  to  be  avoided. 

Molds  and  Dies — Various  methods  to  shape  or  aid  in  shaping 
the  foil  to  the  form  of  the  cavity  with  molds  are  practiced.  The 
following  is  simple  and  quickly  performed.  In  the  case  of  a 
cervical  cavity,  take  an  impression  of  the  cavity  on  the  end  of  a 
cone  of  impression-compound.  For  an  approximal  cavity  fit  a 
small  piece  of  impression-compound  in  the  cavity,  chill  with  water 
from  a  syringe,  and  withdraw  or  tip  out  with  the  point  of  an  ex- 
cavator. A  mold  of  the  cavity  is  then  made  by  again  chilling  the 
impression  with  cold  water  and  pressing  it  against  and  into  the 
surface  of  another  small  piece  of  softened  impression-compound, 
chilling  the  compound,  and  separating  impression  and  mold.  The 
foil  is  then  shaped  in  the  mold  thus  formed  and  fitted  to  the  cavity 
in  the  tooth. 

Another  method,  but  one  which  takes  more  time,  used  by  some 
to  shape  the  matrix  without  fitting  to  the  tooth  in  the  mouth,  is 
to  make  a  mold  with  plaster  from  the  impression-compound  and 
then  boil  the  plaster  in  stearin  to  toughen  it. 

A  much  preferable  method  is  to  place  oxyphosphate  cement 
over  the  impression-compound  and  immediately  add  a  mixture  of 


PORCELAIN  I. \  LAYS. 


36' 


plaster  sufficient  to  shape  up  the  mold.  This  gives  a  mold  with 
sharply  defined  margins,  and  walls  which  will  perfectly  withstand 
any  ordinary  adaptation  of  the  foil  without  chipping  or  fracturing. 
Oxyphosphate  Impressions — Oxyphosphate  is  also  used  to 
take  the  impression  of  the  cavity  as  well  as  form  the  mold.  The 
method  of  procedure  is  as  follows :  Dry  the  cavity  and  surface  of 
the  tooth  and  dust  with  soapstone  applied  with  a  cameFs-hair  brush, 
or  wipe  with  vaselin,  being  careful  to  remove  all  surplus.  Mix  a 
ball  of  oxyphosphate  moderately  stiff,  knead  with  the  fingers,  and 


Fig.  677. 


press  into  the  cavity  and  over  the  margins.  When  set,  remove  the 
impression  from  the  cavity  and  insert  its  base  in  the  surface  of  a 
small  mass  of  plaster  trimmed  either  round  or  square.  The  surface 
of  the  die  is  next  oiled,  and  a  small  mass  of  oxyphosphate  mixed  to 
a  plastic  consistence  is  pressed  over  it.  When  the  oxyphosphate 
has  set,  it  is  first  separated  from  the  die,  then  replaced,  and  enough 
plaster  added  to  complete  the  form  of  the  mold.  By  this  method 
a  very  accurate  mold  of  the  cavity  is  obtainable. 

Process  of  Shaping  a  Matrix  by  a  Mold  or  Die. — The  process 


368  CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 

of  shaping  a  metallic  matrix  to  the  mold  of  a  cavity  is  similar  in 
principle  to  that  used  in  a  cavity  of  a  tooth  in  the  mouth.  To 
facilitate  the  operation  of  swaging,  the  water-bag  method  is  to 
some  extent  used.  The  apparatus  is  illustrated  in  Fig.  677.  The 
mold  is  mounted  on  the  bed-plate  D.  The  foil  to  form  the  matrix 
is  placed  in  position  over  the  mold  and  carefully  depressed  into  the 
cavity  with  a  ball  of  cotton.  Bed-plate,  mold,  and  foil  are  next  set 
in  position  in  the  cylinder  C  D,  the  water-bag  B  placed  over  them, 
and  the  plunger  A  screwed  downward  on  the  water-bag,  pressing 
it  into  the  cavity  and  over  the  surface  of  the  mold  and  swaging 
the  foil  evenly  and  accurately  to  form. 

Discussion  of  Proportion  of  Displacement  by  the  Matrix. — 
A  matrix  swaged  in  a  cavity  represents  on  its  outer  surface  the 
exact  form  and  dimensions  of  that  cavity  and  on  the  inner  surface 
the  same  dimensions  minus  the  thickness  or  displacement  of  the 
foil.  A  matrix  swaged  on  the  surface  of  an  impression  or  die 
drawn  from  a  cavity  will  be  of  the  same  size  as  the  cavity  on  the 
inner  surface  and  plus  the  thickness  or  displacement  of  the  foil  on 
the  outer  surface.  It  has  been  contended  that  a  closer  and  more 
accurately  fitting  inlay  would  be  made  from  a  matrix  the  exact 
form  and  dimensions  of  the  cavity  on  its  inner  surface.  Theoreti- 
cally this  would  seem  to  be  correct,  but  practical  experience  goes 
to  show  that  the  result  is  not  satisfactory,  for  should  the  slightest 
irregularity  exist  on  the  surface  of  the  inlay,  not  having  the 
allowance  of  the  thickness  of  the  foil  as  it  would  if  made  in  the 
usual  manner,  its  adjustment  is  liable  to  be  affected,  and  besides 
a  slight  space  for  the  cement  is  wanting. 

Removal  of  a  Matrix. — The  removal  of  the  matrix  requires 
most  gentle,  delicate  manipulation,  as  it  must  be  accomplished 
without  the  slightest  alteration  of  the  form.  On  account  of  its 
greater  rigidity,  platinum  foil  is  more  easily  removed  than  gold. 
The  cavity  will  generally  have  one  wall  inclined  slightly  more  than 
the  remainder;  a  conformation  which  is  easily  made. 

Gold. — For  the  removal  of  a  gold-foil  matrix,  deep  in  the  cavity, 
at  the  slanting  side,  insert  a  fine-pointed  hoe-shaped  instrument 
into  the  foil,  and  loosen  and  gently  coax  it  from  its  position. 
AVhen  loosened,  take  an  edge  of  the  foil  in  the  tweezers  and  lift 
the  matrix  from  the  cavity. 

Platinum. — A  platinum-foil  matrix  is  generally  best  loosened 
first  at  the  extreme  edge  of  the  burnished  surface. 

Methods  to  Aid   Removal — The  removal  of  a  matrix,  espe- 


POKCELAIX  IX LAYS.  369 

cially  if  of  gold,  is  much  simplified,  and  alteration  of  its  form 
assured  against,  by  filling  it  with  wax.  Soften  and  roll  up  a  pellet 
of  bard,  tough  wax,  a  trifle  larger  than  the  cavity;  introduce  the 
pellet  of  wax  into  the  cavity  of  the  matrix  and  press  it  down  with 
a  flat  burnisher  (Xo.  11,  Fig.  665),  covered  with  pulverized  soap- 
stone  to  prevent  adhesion  of  the  wax  to  the  instrument.  In  ap- 
proximal  cavities  the  pressure  is  best  exerted  with  a  strip  of  tape 
covered  with  the  soapstone.  The  pressure  should  be  steady  and 
direct.  The  wax  should  extend  over  the  edge  of  the  cavity  onto  the 
foil,  but  at  no  point  beyond  its  margin,  as  adhesion  of  the  wax  to 
the  tooth  would  interfere  with  the  removal  of  the  matrix.  A 
stream  of  cold  water  from  a  syringe  is  next  thrown  on  the  wax, 
and  the  matrix  is  then  started  and  removed  from  the  cavity.  The 
wax  in  the  case  of  a  platinum  matrix  can  be  removed  by  seizing  the 
edge  of  the  foil  with  tweezers  or  clamp  and  holding  it  open  end 
downward  for  a  moment  in  a  cup  of  water  that  is  simmering  just 
at  the  boiling-point,  or,  the  matrix  can  be  invested  in  marble- 
dust  and  plaster  and  the  wax  then  removed.1 

Investing  the  Matrix — In  the  use  of  a  1/1000-inch  platinum- 
foil  matrix,  for  high-fusing  porcelain,  investment  of  the  matrix 
is  not  generally  practiced.  Gold-foil  or  a  1/2000  platinum-foil 
matrix  is  usually  invested,  owing  to  the  great  shrinkage  which 
occurs,  especially  in  the  fusing  of  the  first  application  of  the  porce- 
lain body.  Dr.  Jenkins's  method  of  investing  a  gold-foil  matrix, 
in  connection  with  the  use  of  his  low-fusing  porcelain,  is  given 
below  : 

]\Iix  finely  powdered  asbestos  with  water  to  the  desired  con- 
sistence, and  place  in  the  platinum  cup,  which  is  included  in  his 
outfit  and  is  illustrated  in  Fig.  678,  sufficient  of  it  to  imbed  the 
matrix.     Lay  the  gold-foil  matrix  on  the 
surface  of  the  asbestos,  slightly  tap  the 
cup,  and  the  matrix  will  settle  down  in 
place  in  the  asbestos.     Should  some  of  the 
walls  stand  high,  a  little  of  the  asbestos 
should  be   carried  under  them  with  the 
point  of  a  camel's-hair  brush,  or  an  ivory 
spatula,    so    that    the    matrix    is    every- 
where equally  supported.     Fig.   678  shows  an  invested  matrix. 

For  high-fusing  porcelain,  or  when  wax  is  used  in  a  gold  matrix 

1  Gum-camphor  has  lately  been  recommended  in  preference  to  wax.      The 
camphor  is  compressed  in  the  matrix  and  removed  by  alcohol  or  heat. 


370 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


to  assist  its  removal,  the  matrix  must  be  invested  just  as  for  the 
formation  of  a  gold  inlay,  in  marble-dust  and  plaster.  Take  very 
finely  ground  calcined  marble-dust  two  parts,  and  plaster  one  part. 
First  thoroughly  mix  them,  and  then  add  enough  water  to  form  a 
moderately  thin  paste;  place  a  proper  quantity  of  the  investing 
material  on  a  piece  of  paper  on  the  bench,  set  the  matrix  on  the 
center,  and  let  it  settle  into  the  investment.  A  few  taps  on  the 
bench  alongside,  sufficiently  hard  to  jar  it,  will  assist  the  settling. 
When  the  investment  has  set,  the  wax  is  washed  out  with  a  stream 
of  boiling  water  and  the  investment  trimmed  as  small  as  it  properly 
can  be.  jSText,  dry  and  heat  over  a  Bunsen  flame  until  the  invest- 
ment approaches  a  red  heat,  then  let  it  cool,  and  the  matrix  is 
ready  for  the  application  of  the  porcelain. 

Application  of  Porcelain  Body. — The  methods  of  procedure 
in  applying  the  body  with  low-  and  high-fusing  porcelains  are 
quite  similar,  irrespective  of  the  degree  of  heat  required.  A 
description  of  the  use  of  one  style  will,  in  a  measure,  explain  the 
subject  for  both. 

The  Jenkins  Low=Fusing:  Application  and  Fusing — This  is 
a  porcelain  introduced  by  Dr.  N.  S.  Jenkins,  of  Dresden,  Ger- 
many. As  indicated  by  the  pyrometer  it  fuses  at  1580°  F.  It 
a    dense,    hard    porcelain,   with   a  considerable   degree   of 

crushing  strength,  and  resembles 
in  appearance  the  porcelain  of 
an  English  tooth  more  than  that 
of  the  American.  The  follow- 
ing is  an  explanation  of  the  use 
of  the  Jenkins  porcelain  and  the 
appurtenances  connected  with  it. 
which  are  illustrated  in  Fig.  679. 
Place  upon  the  agate  palette  the 
required  quantity  of  the  body  of 
the  selected  color,  and  mix  it 
with  absolute  alcohol.  With  the 
small,  thin  blade  of  the  spatula 
carry  the  well-moistened  body 
into  the  matrix  and  fill  it  up  to 
but  not  over  the  edges.  If  in 
applying  the  powder  it  becomes 
too  dry  in  the  matrix,  drop  on 
its  .surface  from  the  point  of  the 


fo 


Fig.  070. 


PORCELAIN  INLAYS.  371 

glass  drop-tube  a  little  more  alcohol.  During  the  packing  aid  the 
precipitation  of  the  particles  of  the  body  by  a  few  light  taps  on 
the  side  of  the  f  using-cup  or  on  its  handle. 

Method  of  Fusing. — Put  the  cover  on  the  fusing-cup,  with  the 
opening  toward  the  handle.  Hold  the  cup  over  the  hole  in  the 
heater  and  turn  a  very  fine  flame  from  the  gas  blowpipe  onto  the 
handle,  about  an  inch  from  the  f using-cup,  for  the  purpose  of 
gradually  imparting  heat  to  the  asbestos  and  slowly  evaporating 
the  alcohol.  This  must  not  be  done  hurriedly,  as  the  moisture  is 
to  be  evaporated,  not  boiled  out.  Next,  turn  the  flame  upon  the 
bottom  of  the  cup,  slowly  and  gently  increasing  both  flame  and 
draft  from  the  foot-bellows.     (See  Fig.  679.) 

The  process  of  fusing  can  be  seen  clearly  through  the  opening 
of  the  platinum  cover.  When  the  powder  begins  to  fuse,  hold  the 
flame  and  draft  as  it  is,  and  do  not  try  to  accelerate  the  melting  by 
rapidly  increasing  the  heat.  When  the  work  approaches  the  fusing 
stage,  the  fact  is  indicated  by  a  dark  shade  which  for  a  moment 
passes  over  the  porcelain  body,  caused  probably  by  combustion  of 
a  small  quantity  of  starch  introduced  as  an  ingredient  to  assist  in 
holding  the  particles  of  the  compound  together.  The  body  then 
again  assumes  a  light  shade,  and  at  about  a  red  heat  fuses  suffi- 
ciently for  a  primary  or  biscuit  bake,  when  the  application  of  heat 
must  be  instantly  stopped.  To  cool  the  investment  remove  the 
cover  of  the  cup.  The  cooling  can  be  hastened  by  holding  the 
bottom  of  the  cup  against  the  surface  of  cold  water,  but  care  must 
be  taken  that  the  water  does  not  enter  the  cup.  In  the  first  fusing 
the  body  globulates  and  contracts  nearly  one-half  the  size  of  the 
cavity  of  the  matrix,  a  characteristic  of  low-fusing  bodies.  The 
fused  body  in  the  matrix  is  moistened  with  alcohol  and  more  body 
is  applied  to  fill  the  vacancy  caused  by  the  shrinkage.  If  the 
investment  is  wet  with  the  alcohol  in  the  application,  it  will  not 
injure  it. 

For  the  second  bake  apply  a  small  flame  at  first  on  the  handle 
and  presently  a  blue  flame  from  the  alcohol  will  appear  at  the 
opening  of  the  cover.  Let  it  burn  until  quite  consumed  and  then 
fuse  the  porcelain  body  as  before.  A  third  application  of  body  is 
necessary  for  exactness  of  edges  and  contour.  In  the  third  or  final 
bake,  the  heat  is  carried  higher  than  in  the  previous  ones,  up  to  the 
actual  fusing-point  of  the  porcelain  body,  a  "glazing  heat,"  to  im- 
part a  glossy  surface.     It  is  well  to  examine  the  inlay  with   a 


372  CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 

magnifying  glass,  to  be  sure  that  the  edges  are  exact,  both  in 
applying  the  body  and  after  fusing.  The  tendency  on  the  part  of 
the  operator,  in  the  beginning,  is  to  build  out  too  much,  but  after 
some  experience  he  learns  to  get  exactly  the  form  and  fullness 
desired.  After  the  final  baking  it  is  better  to  let  the  piece  cool 
somewhat  slowly. 

Use  of  Electric  Furnace  for  Baking  Low=Fusing  Porcelain — 
This  style  of  porcelain  can  be  baked  to  advantage  in  an  electric 
furnace.  The  heat  of  the  muffle  is  raised  a  little  above  the  re- 
quired fusing  point  of  the  porcelain,  the  tray  containing  the  work, 
uncovered,  is  gradually  introduced,  where  being  exposed  to  view 
the  process  of  fusing  is  seen  and  determined.  Aided  by  the  pyrom- 
eter, the  heat  can  be  accurately  defined  and  fusing  of  the  porce- 
lain conducted  without  the  expertness  required  in  the  use  of  the 
gas  method. 

The  Jenkins  porcelain  fuses  at  about  1580°  F.  Guided  by 
the  pyrometer,  the  primary  bakes  can  be  made  at  1480°  to  1500° 
F.,  and  for  the  final  one  the  heat  raised  to  1580°  F.,  at  which 
degree  it  should  be  held  for  about  ten  seconds  and  the  current 
instantly  turned  off. 

The  Application  of  High=Fusing  Porcelain  Body — The  appli- 
cation of  high-fusing  porcelain  body  to  platinum  matrices,  though 
similar  to  that  described  in  relation  to  low-fusing,  differs  in  im- 
portant minor  details.  The  shade  of  body  selected  is  wet  with 
distilled  or  filtered  water  and  dried  with  blotting-paper  to  the  con- 
sistence of  a  paste.  The  matrix  may  be  invested  or  not.  If  not 
invested,  it  is  held  by  the  edge  with  pliers  or  clamp-tweezers.  (See 
Fig.  680.)  The  porcelain  body,  of  a  dough-like  consistence,  is 
carried  on  a  spatula,  or  preferably  the  point  of  a  very  small 
camel's-hair  brush,  a  portion  at  a  time,  and  dropped  in  position  in 
the  matrix,  and  by  sharp  taps  on  the  back  of  the  tweezers,  or 
by  vibrations  caused  by  drawing  the  corrugations  on  the  handle  of 
the  spatula  shown  in  Fig.  658  across  them,  the  body  is  settled 
down  in  the  matrix.  This  tapping  or  vibrating  packs  the  particles 
of  porcelain  closely  together  and  sends  the  moisture  to  the  surface 
at  each  tapping,  when  it  should  be  absorbed  with  a  piece  of  blot- 
ting-paper trimmed  to  a  point.  Through  this  condensation  of  the 
porcelain  body,  the  shrinkage  which  naturally  occurs  in  the  baking 
is  reduced  to  the  minimum,  and  porosity  is  avoided.  The  first  ap- 
plication of  body  should  not  be  allowed  to  come  quite  to  the  edge 


PORCELAIN  INLAYS. 


373 


Fig.  680. 


of  the  cavity  of  the  matrix.  The  matrix  if  not  invested  is  set  on 
a  bed  of  silex  on  a  small  fire-clay  slab  or  in  a  platinum  pan,  such 
as  are  now  made  and  sold  for  the  purpose. 

First  Bake.— The  slab  is  placed  on  the  shelf  in 
front  of  the  muffle  to  evaporate  the  moisture  from 
the  body.  It  is  then  slowly  advanced  into  the 
muffle  and  the  body  given  the  primary  bake, 
which  should  be,  as  gaged  by  the  pyrometer,  from 
150°  to  200°  below  the  actual  fusing-point  of  the 
make  of  porcelain  body.  Some  high-fusing  com- 
pounds fuse  nearly  200°  above  others.  The  pri- 
mary bake  under  such  condition  must  be  calcu- 
lated accordingly,  or  determined  by  testing.  The 
heat  should  be  only  sufficient  to  well  unite  the 
particles  and  give  the  body  a  slight  glaze.  In  this 
primary  bake  considerable  shrinkage  takes  place. 
The  larger  the  matrix,  the  more  noticeable  the 
shrinkage  will  be. 

Second  Bake. — The  matrix  is  again  placed  in 
the  cavity,  and  while  firmly  held  in  position  by 
pressure  exerted  on  the  center  of  the  porcelain, 
the  platinum,  which  is  always  slightly  drawn  from 
the  margins  by  the  contraction  of  the  porcelain,  is 
reburnished  at  the  edges  of  the  cavity.  In  this 
second  burnishing  the  platinum,  which  is  then 
extremely  soft  from  the  annealing  it  received  in 
the  baking  of  the  body,  is  additionally  thinned  at 
the  margins  of  the  cavity  and  is  adapted  with  great 
accuracy.  More  body  is  applied,  filling  the  ma- 
trix to  the  edge,  and  a  second  bake  given  at  a  heat 
a  few  degrees  higher  than  the  previous  one. 

Final  Bake. — For  the  final  bake  all  new  imper- 
fections in  the  porcelain  are  filled  in  and  a  heat 
applied  sufficient  to  perfectly  coalesce  the  particles 
and  give  the  work  a  uniform  glazed  surface.     For  this  final  bake 
the  heat  should  be  run  up  exactly  to  the  fusing-heat  of  the  porce- 
lain and  maintained  there  for  from  fifteen  to  twenty  seconds,  and 
then  instantly  shut  off  and  the  work  gradually  cooled. 

Comparative  Heat  of  the  Bake — Should  the  circumstances 
require  more  than  two  primary  bakes,  the  full  fusing-heat  of  the 
porcelain  should  be  avoided  until  the  final  one. 


374  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Removal  of  a  Foil  Matrix. — When  the  inlay  is  cool,  always 
first  wet  it  with  water  before  handling,  then,  if  invested,  remove 
it  from  its  investment.  With  tweezers  gently  and  slowly  bend 
back  the  foil  from  the  edges  and  it  will  usually  strip  off  in  one 
piece.  If  any  shreds  of  foil  adhere  to  the  inlay,  remove  them  with 
a  fine  excavator. 

Preparation  for  Cementation. — For  the  purpose  of  retention 
of  inlays,  a  few  grooves  are  made  on  the  bottom  and 
Fig.  G81.       sides  in  the  porcelain  with  a  small  diamond  disk  (see 
C~")  (      J     Fig.   681)  or  the  gloss  removed  with  a  small  cone- 
shaped  "Gem"  point  to  facilitate  adhesion  of  the  ce- 
ment. 

Methods  of  Etching  with  Acid  or  a  Diamond. — 
If  the  inlay  is  too  small  to  handle  conveniently,  the 
gloss  can  be  removed  by  covering  the  face  and  mar- 
gins of  the  base  with  wax  and  applying  hydrofluoric 
acid  for  a  few  minutes.  An  inlay  can  1  e  quickly 
etched  over  the  entire  surface  except  at  the  extreme 
edge  where  it  meets  the  margin  of  the  cavity,  with  a  diamond 
point  in  the  engine  hand-piece,  aided  by  a  lens  to  magnify  the 
part.  The  lens,  for  convenience,  should  be  mounted  on  a 
stand  like  that  used  by  wood  engravers.  By  this  method  nearly 
the  entire  cavity-snrface  of  the  porcelain  is  divested  of  its  glaze  and 
ronghened.  The  adhesion  of  the  cement  to  such  a  surface,  which 
is  much  more  porous  than  when  merely  acted  on  by  hydrofluoric 
acid,  is  absolute,  and  displacement  of  the  inlay  from  lack  of  at- 
tachment of  the  cement  is  positively  assured  against.  Excessive 
and  deep  indentation  of  an  inlay  with  disks  weakens  it  and  renders 
it  liable  to  fracture  in  insertion  or  use.  In  shallow  inlays  it  is 
liable  also  to  affect  the  shade. 

To  Aid  Adjustment  in  Cementation. — In  the  cementation  of 
an  inlay  it  is  well  to  be  able  instantly  to  insert  it  correctly  in  the 
cavity,  as  its  removal  and  reinsertion  after  the  cement  is  applied 
are  objectionable.  The  inlay  after  the  fitting  is  completed  may  be 
laid  upon  the  operating  case  in  such  wise  that  there  will  be  no 
uncertainty  in  carrying  it  straight  to  its  correct  position.  Another 
way  is  to  insert  the  inlay  before  the  cement  is  applied,  and  after 
drying  the  surfaces  mark  corresponding  parts  of  tooth  and  inlay 
with  a  fine-pointed  pen,  drying  the  ink  with  hot  air.  (See  Fig. 
682.)     The  marks  form  an  unerring  guide  to  the  proper  relative 


FORCE  LAI  y  IX  LAYS.  375 

position  of  the  inlay.      A  few  grooves  may  be  made  in 

the  walls  of  the  cavity  to  favor  the  cement,  but  this  is     Fig.  682. 

not  always  considered  necessary. 

Cementation. 

Requirements:    Effect  on  Color  of  Porcelain. — Oxy- 

phosphate  cement  is  almost  universally  used  for  the 
fomentation  of  porcelain  inlays.  Its  adhesiveness  to  both 
tooth-structure  and  unglazed  porcelain  renders  it  most  suitable  for 
the  purpose,  but  its  solubility  at  the  edges  of  an  inlay  is  what 
chiefly  raises  the  question  of  durability  of  this  class  of  operations. 
The  durability  of  porcelain  inlay-work  depends  on  the  closeness  of 
the  meeting  edges  of  inlays  with  those  of  the  enamel  at  every  point. 
The  opaqueness  of  this  cement,  owing  to  the  translucency  of  the 
porcelain,  frequently  very  materially  affects  the  shade  of  a  ce- 
mented inlay.  The  effect  of  the  cement  on  the  shade  can  be  quite 
accurately  determined  previously  by  first  mixing  a  little  of  the 
powder  of  the  cement  with  water,  placing  it  in  the  cavity,  ami 
inserting  the  inlay.  The  shade  of  the  cement  should  accord  well 
with  that  of  the  inlay  or  tooth,  but  be  a  trifle  lighter. 

Operation  of  Cementation. — Successful  cementation  of  inlays 
largely  depends  on  the  manner  in  which  the  oxyphosphate  is  used, 
as  well  as  on  its  quality.  The  cement  should  be  most  thoroughly 
mixed,  and  its  consistence  should  be  as  nearly  that  of  a  thick  paste 
as  possible  without  too  great  an  impairment  of  its  adhesiveness.  A 
cream-like  consistence,  such  as  is  used  for  gold  cap-crowns,  is  not 
reliable.  A  cement  which  can  be  mixed  thick  and  still  retain  its 
adhesiveness,  and  yet  in  that  condition  easily  ooze  out  from  under 
and  around  an  inlay  at  the  edges  under  properly  exerted  pressure, 
is  the  most  suitable.  As  the  action  of  phosphoric  acid  on  the  ordi- 
nary steel  spatula  is  liable  to  affect  the  color  of  the  cement,  one 
formed  on  the  end  of  an  orange-wood  stick  is  the  most  suitable  to 
use  for  the  purpose  of  mixing  the  cement. 

The  inlay  and  cavity  having  been  dried  perfectly,  a  little  of  the 
cement  is  smeared  in  every  part  of  the  cavity  and  on  the  sides  and 
bottom  of  the  inlay,  and  especially  in  any  groove  present.  The 
inlay  is  then  placed  in  the  cavity  and  gradually  pressed  home. 
Before  it  is  quite  in  place,  the  surplus  cement  should  be  removed 
from  the  surface,  the  inlay  carefully  examined  to  see  if  it  is  ex- 


376  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

actly  in  proper  position,  and  the  final  pressure  given  with  a  prop- 
erly shaped  piece  of  wood.  The  final  pressure  should  be  gentle 
and  elastic,  and  exerted  on  the  center  of  the  inlay,  until  all  surplus 
'cement  has  oozed  out.  In  approximal  cavities  a  piece  of  tape  or 
floss  silk  may  be  used  to  press  an  inlay  to  place,  but  a  wedge- 
shaped  piece  of  wood  is  to  be  preferred.  If  the  rubber-dam  is 
used,  leave  it  on  until  the  cement  has  set.  Varnish  should  be 
painted  over  the  inlay.  At  a  subsequent  sitting,  particles  of  oxy- 
phosphate  which  may  be  still  clinging  to  the  tooth  or  inlay  should 
be  removed.  If  on  examination  the  porcelain  should  be  found  to 
improperly  project  beyond  the  surface  of  the  enamel  at  any  point, 
it  should  be  reduced  with  finishing  disks  or  strips,  or  Arkansas 
stone  points. 


CHAPTER    VII. 
Special  Operations,  Rod  Inlays,  and  Points  to  Bear  in  Mind. 

large  contour  inlays— use  of  pieces  of  porcelain  teeth  -use 
of  successive  grades  of  bodies— subject  of  occlusion — 
porcelain  inlays  in  combination  with  gold  or  amalgam 
fillings — atrophy  and  erosion — porcelain  tips — porcelain 
shoulders  preferable  to  pins  for  retention— wire  loop. 

Rod  Inlays. 

preparation  of  the  cavity — the  rod  inlay— cementation  and 
finishing— use  of  porcelain  teeth  to  form  inlays. 

Points  to  Bear  in  Mind. 

to  facilitate  matrix  adaptation  in  cervical  cavities — to  over- 
come contraction  of  body— to  aid  removal,  and  remedy  tear 
of  matrix — advantages  of  the  use  of  a  foundation  body 
in  contour  operations— use  of  lens— porosity  of  porcelain 
—time-saving  in  inlay  work— edges  of  inlays— small  inlays 
—effect  of  cement  on  shade — requirements  in  inlay-work— 
conservative  limitations  of  inlay-work. 

Special  Operations. 

Large  Contour  Inlays. — When  considerable  contour  is  given 

or  a  corner  is  built  out,  for  instance,  in  a  case  such  as  is  represented 

in  Fig.  683  and  others  of  that  character,  the  porce-         „ 
,.,,,,  .  .   .  ,  i  Fig.  6S3. 

lam  should  always  be  set  at  a  right  angle  to  the 

biting  or  incising  edge  of  the  tooth  under  treatment, 
as  shown  at  A,  or  chipping  is  liable  to  occur.  In 
this  and  all  such  cases  a  projecting  horn  of  the 
porcelain  (B)  will  make  a  much  stronger  anchor- 
age than  a   platinum  pin.      A  platinum  pin  in  a 


37S  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

small  mass  of  porcelain  has  a  tendency  to  weaken  it  by  breaking 
up  the  continuity  of  its  structure. 

Use  of  Pieces  of  Porcelain  Teeth — In  building  up  corners  of 
large  contours  a  piece  of  a  porcelain  tooth  of  the  exact  shade  can 
be  placed  in  the  matrix,  and  the  body  built  around  and  over  it. 
The  applied  piece  of  fused  porcelain  by  its  presence  lessens  the 
usual  proportion  of  shrinkage  of  the  inlay  baking  and  simplifies 
the  construction  of  'a  sharp  corner.  In  the  use  of  the  high-fusing 
porcelain,  after  it  has  been  baked  in  position  in  the  matrix,  the 
work  may  be  adjusted  in  the  tooth,  its  position  examined,  and, 
should  any  point  of  the  piece  of  porcelain  project  excessively,  it 
can  be  trimmed  off  with  a  corundum-wheel.  The  porcelain  should 
then  be  washed  and  cleaned  of  the  debris  resulting  from  the 
grinding. 

Use  of  Successive  Grades  of  Bodies. — The  use  of  successive 
grades  of  high-fusing  porcelain,  commencing  with  a  very  high- 
fusing  foundation,  and  followed  by  lower  and  still  lower-fusing 
bodies,  often  simplifies  the  operation  of  building  out  a  difficult 
corner.  In  such  a  case  each  application  should  be  biscuited  and 
fused  before  the  next  lower-fusing  grade  is  added. 

Occlusion  in  Close  Bite. — When  a  large  corner  is  built  0:1  an 
upper  incisor,  if  the  bite  is  close,  the  porcelain  should  be  depressed 
at  the  point  of  occlusion  with  the  lower  teeth,  and  enough  of  the 
incisal  edge  of  the  lower  antagonizing  tooth  should  be  ground  off 
to  leave  a  slight  space — say  that  of  thin  cardboard — between. 
Porcelain  Inlays  in  Combination  with  Gold  or  Amalgam 
0g4  FilSings — In  a  case  of  combined  approximal  and  cervical 
decay,  where  the  shape  is  unfavorable  to  the  formation  of 
;m  entire  porcelain  inlay,  or  undesirable,  fill  the  approx- 
imal cavity  with  cohesive  gold,  extending  it  into  the  cer- 
vical cavity,  trim  the  edge  of  the  gold,  and  then  form  and 
insert  the  inlay  partly  in  the  latter,  as  illustrated  in  Fig. 
684.  Large  amalgam  fillings,  especially  in  either  the 
liicuspids  or  molars,  may  be  treated  in  a  similar  manner. 
Atrophy  and  Erosion. — In  atrophy  of  the  enamel,  as  illus- 
trated in  Fig.  GS5,  porcelain  inlay-work  is  specially  suitable.  In 
cases  of  erosion,  where  shrinkage  of  the  gum  causes  exposure  of  a 
portion  of  the  root,  as  shown  in  Fig.  686,  the  section  of  the  inlay 
over  the  root  can  be  enameled  with  gum-colored  porcelain.  Gum 
enamel  fuses  at  a  lower  heat  than  the  porcelain  it  accompanies,  and 


SPECIAL  OPERATIONS  AXD  ROD  IX LAYS. 


379 


is  to  be  applied  after  the  final  baking  of  the  inlay,  but  before  re- 
moval from  the  matrix. 

Fig.  685. 


Fig.  686. 


Fractures. 

Porcelain  Tips — Porcelain  work  is  specially  adapted  to  the 
restoration  of  portions  of  natural  teeth  which  have  been  broken 
off   and   of   those   which   have 

suffered  through  some  form  of  FlG-  os'- 

abrasion. 

Pig.  687  illustrates  a  case  of 
atrophy  in  which  the  tips  of  the 
central  incisors  were  contoured 
with  porcelain.  The  right  cen- 
tral shows  the  porcelain  in  posi- 
tion, the  left  the  porcelain  tip 
ready  to  be  adjusted.  A  dove- 
tailed cavity  was  first  formed  in  the  central  portion  of  the  section 
to  be  tipped  or  contoured.  A  piece  of  platinum  foil  was  adapted 
to  the  cavity,  and  high-fusing  porcelain  body  baked  thereon  as 
already  described.  The  platinum  foil  was  then  removed  and  the 
tip  cemented  in  position. 

To  form  an  extremely  strong  porcelain  tip,  Dr.  Land  selects  an 
S.  S.  White  Dental  Manufacturing  Company's  porcelain  tooth  of 
the  correct  shade,  pulverizes  finely  the  portion  corresponding  to 


380  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

the  part  to  be  restored,  and  uses  the  powder  as  the  body  to  form 
the  tip.  A  very  high  heat  is  required  to  fuse  the  porcelain  of 
artificial  teeth,  but  the  greatest  possible  strength  in  a  porcelain  tip 
is  secured  by  the  use  of  such  a  body. 

Porcelain  Shoulders  Preferable  to  Pins  for  Retention. — For 
the  retention  of  a  porcelain  tip,  a  shoulder  of  the  porcelain,  such 
as  is  illustrated  in  Fig.  687,  is  preferable  to  forming  the  tip  with 
a  loop  of  wire  or  with  platinum  pins,  which  are  to  be  cemented 
in  holes  drilled  in  the  tooth-substance.  The  presence  of  pins,  as 
lief  ore  mentioned  in  regard  to  other  operations,  weakens  so  small 
a  piece  of  porcelain  by  breaking  up  the  continuity  of  its  structure. 
The  pins  do  not  form  for  it  as  secure  or  strong  an  attachment  as 
a  porcelain  anchorage  of  moderate  size. 

Wire  Loop.- — In  cases  of  fracture  in  which  porcelain  tips  are 
required,  and  the  existing  conditions  do  not  permit  of  the  removal 
of  sufficient  tooth-structure  to  form  a  porcelain  anchorage,  the 
use  of  pins  must  be  resorted  to.  In  such  a  case,  after  the  holes 
have  been  formed, — there  should  not  be  more  than 
two, — and  the  parts  properly  prepared,  the  surface  of 
the  fractured  part  is  capped  with  platinum  foil  punc- 
tured over  the  holes  and  the  pins  inserted.  The  wire 
to  form  the  pins  should  be  of  about  ISTo.  21  gage.  It 
should  be  first  rolled  under  a  fine  flat  file  to  slightly 
roughen  its  surface.  The  pins  should  extend  from  the 
foil,  or  the  wire  forming  them  be  shaped  in  a  loop,  as 
shown  in  Fig.  688.  While  the  platinum  cap  and  pins 
are  in  position  on  the  tooth,  a  small  quantity  of  a  very 
high-fusing  porcelain  or  foundation  body  is  applied  to 
the  center  of  the  cap  and  closely  around  the  pins.  The  excess  of 
moisture  is  absorbed  with  blotting-paper  and  the  surplus  body  re- 
moved with  a  small  brush  from  around  the  margins  of  the  cap. 
The  wire  or  loop  is  then  seized  and  the  whole  gently  removed 
from  the  mouth  and  given  a  biscuit  bake.  On  removal  it  is  read- 
justed on  the  tooth.  The  shrinkage  of  the  foundation  body  is 
compensated  for  by  the  addition  of  more  body,  and  it  is  again  in- 
serted in  the  furnace  and  then  given  a  bake  at  the  fusing-heat  of 
the  porcelain.  If  the  extension  of  the  loop  of  wire  above  and 
across  the  surface  of  the  cap  occupies  more  space  than  the  size  and 
form  of  the  part  to  be  restored  will  allow,  the  loop  should  be  bent 
down  a  little  against  the  surface  of  the  cap  or  be  partly  or  entirely 


SPECIAL  OPERATIONS  AND  ROD  INLAYS.  3gl 

removed  by  grinding,  leaving  only  the  pins.  Should  the  latter 
course  be  necessary,  the  pins  will  then  be  held  in  position  by  the 
foundation  body  which  has  been  fused  around  them.  The  cap  is 
next  placed  on  the  tooth  and  the  margins  of  the  platinum  bur- 
nished closely  around  that  of  the  fracture  and  the  formation  of  the 
tip  completed  with  porcelain  body  which  fuses  at  a  lower  heat  than 
that  already  used.  After  the  final  fusing  of  the  porcelain  the  foil 
is  torn  from  the  base.  It  will  not  adhere  to  the  pins,  not  having 
been  soldered  to  them.  The  burnishing  of  the  foil  at  the  margins 
of  the  cap  after  the  first  baking  slightly  reduces  its  gage  in  com- 
parison with  the  central  portion  and  tends  to  effect  a  closer  fit  for 
the  porcelain  at  that  part. 

Small  Fractures.- — Fractures  of  the  incisal  edges  of  the  in- 
cisors, of  the  character  and  as  small  as  those  illustrated  in  Fig. 
689,  cannot  be  restored  with  porcelain.     The  fractured   part   is 

Fig.  689.  Fig.  690. 


usually  of  enamel  entirely,  and  the  area  to  be  operated  on  is  so 
small  that  a  reliable  anchorage  for  the  porcelain  is  seldom  ob- 
tainable. 

When  an  imperfection  of  the  enamel,  decay,  or  a  fracture  in- 
volves only  the  central  section  of  a  moderately  thick  incisal  edge 
of  an  incisor  or  cuspid,  that  part  may  be  inlaid  with  porcelain  by 
shaping  the  cavity  as  illustrated  in  Fig.  690. 

In  cases  where  the  fracture  or  imperfection  involves  a  loss  of 
nearly  one-half  of  the  natural  crown,  an  artificial  crown  is  prefer- 
able. 

Rod  Inlays. 

The  use  of  rod  inlays  is  specially  adapted  to  fillings  such 
as  are  too  small  to  be  formed  by  fusing  porcelain  in  a  foil  matrix 
of  the  cavity,  or  in  circular  cavities  or  in  those  which  can  be 
shaped  round,  on  the  labial  surfaces  of  the  upper  incisor  teeth. 

Preparation  of  the  Cavity. — The  cavity  to  be  inlaid  is  shaped 
with  a  fine-cut  wheel-bur  of  the  style  shown  in  Fig.  691,  perfectly 


382 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


round,  with  straight  walls,  over  one-thirty-second  and  approxi- 
mating one-sixteenth  of  an  inch  in  depth.  As  an  inlay  of  this 
style  cannot  very  well  be  manipulated  of  a  diameter  less  than 
No.  20  gage,  the  cavity  requires  to  be  enlarged  to  at  least  that 
size. 

The  Rod  Inlay. — The  inlay  is  made  from  a  portion  of  one  of 
the  porcelain  rods  (Fig.  692)  or  circular  pieces  of  porcelain  (Fig. 


Fig.  691. 


w     %„i^     *w 


Fig.  692. 


I 


Fig.  693. 

6    0    0 


693)  manufactured  for  the  purpose.  The  porcelain  is  mounted 
with  shellac  on  either  end  of  one  of  the  mandrels,  Fig.  694,  marked 
1,  2,  3,  and  gradually  ground  down  in  the  hand-piece  of  the  dental 
engine  to  fit  the  cavity,  using  a  flat  piece  of  corundum  as  shown 
in  Fig.  694,  and  fine  sand  or  emery  paper  in  the  final  reduction. 
A  micrometer  gage  is  an  aid  in  measuring  the  size  of  the  bur  to 
be  used  and  the  diameter  of  the  inlay  during  the  reduction  and 
fitting. 

Cementation  and  Finishing. — The  inlay  when  fitted  is  de- 
tached from  the  mandrel,  the  cavity  very  slightly  undercut,  and 
the  inlay,  without  being  ground  or  notched. — cement  will  adhere 
tenaciously  to  the  surface  of  the  ground  porcelain — cemented 
with  oxyphosphate.  When  the  cement  has  set  perfectly,  the 
porcelain  which  protrudes  above  the  surface  of  the  enamel  is 
ground  level  with  small  corundum-points  or  wheels  and  finished 
with  Arkansas  stone  points.     Figs.  696  and  697  show  inlays  that 


SPECIAL    OPERATIONS    AND  ROD  INLAYS. 


383 


are  best  inserted  by  this  method  where  imperfections  or  cavities 
exist. 

Use  of   Porcelain   Teeth   to   Form    Inlays. — Where  the  por- 


FlG.  G94. 


Fig.  G95. 


tion  of  the  tooth  to  be  inlaid  is  in  the  region  where  blending  of 
shades  or  colors  occurs,  a  porcelain  tooth  may  be  selected  matching 
the  natural  tooth,  and  the  inlay  cut  from  the  Fl(.  696  -pia  697 
corresponding  location.  The  work  of  cutting 
the  required  section  of  the  porcelain  can  be 
much  simplified  by  the  use  of  diamond  trephine 
burs  manufactured  for  this  purpose  (Fig.  695), 
which  correspond  in  size  with  the  set  of  burs 
made  for  shaping  the  cavities. 


Points  to  Bear  in  Mind. 

To  Facilitate  Matrix  Adaptation — In  the  adaptation  of  a 
matrix  in  an  approximal  cavity  the  process  is  greatly  simplified 
by  the  presence  of  abundant  space  and  freedom  from  interference 
by  the  gum-septum.  In  cases  where  cervical  decay  extends  under 
the  gum-margin,  the  cavity  should  be  previously  packed  with  cot- 
ton or  gutta-percha,  and  the  gum  pressed  from  normal  position 
sufficiently  to  fully  expose  the  edge  of  the  cavity  and  admit  per- 
fect adaptation  of  the  matrix.  The  method  of  packing  the  cavity 
of  the  matrix  with  wax,  in  such  a  case,  is  to  be  recommended, 


384  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

especially  if  gold  foil  is  used,  as  the  wax  will  maintain  the  posi- 
tion of  the  foil  should  any  point  press  against  the  gum. 

To  Overcome  Contraction  of  Body. — In  the  use  of  any  grade 
of  porcelain  body  the  most  extensive  shrinkage  occurs  in  the  first 
baking.  The  body  contracts  from  the  sides  toward  the  center.  To 
cause  the  contraction  to  take  place  from  the  center  toward  the 
sides  it  has  been  suggested  to  place  the  body  in  a  ring  around  the 
sides  of  the  matrix;  this,  however,  is  seldom  practical.  Instead,  a 
little  of  the  body  may  be  removed  from  the  center  of  the  filled 
matrix.  The  effect  of  shrinkage  is  controlled  to  a  considerable 
extent  by  serrating  the  body,  thus  dividing  it  into  several  small 
sections. 

To  Aid  Removal,  and  Remedy  Tear  of  Matrix. — The  removal 
of  a  matrix  from  a  cavity  is  often  facilitated  and  the  presence  of  a 
large  tear  in  the  bottom  overcome  by  filling  the  matrix  with  the 
porcelain  body,  on  the  same  principle  that  wax  is  often  applied, 
before  removing  it  from  the  cavity.  The  body  is  placed  in  the 
cavity  and  compressed  with  a  strip  of  tape  or  pellet  of  cotton  to 
condense  it  and  absorb  the  moisture.  The  surplus  is  then  brushed 
off  with  a  camel's-hair  brush,  and  the  matrix  removed  and  baked. 
In  the  use  of  high-fusing  porcelain  in  such  cases  a  foundation 
body  had  best  be  applied,  especially  when  the  matrix  is  torn. 

Advantages  of  the  Use  of  a  Foundation  Body  in  Contour 
Operations. — In  contour  operations  it  is  advisable  to  use  a  founda- 
tion or  basal  body  in  the  first  baking,  as  it  fuses  at  a  higher  heat 
than  the  body  used  to  construct  the  remaining  portion.  The  use 
of  a  basal  body  is  advisable  especially  in  a  case  where  the  bottom 
of  the  platinum  matrix  is  cracked  or  broken.  In  the  first  baking 
it  covers  over  the  breaks  and  remains  intact  during  the  application 
of  the  remainder  of  the  lower-fusing  porcelain  which  is  applied 
to  shape  or  build  up  the  inlay,  and  gives  form  and  rigidity  to  the 
.  base.  As  a  basal  body  fuses  at  a  higher  heat  than  that  subse- 
quently applied,  it  should  be  both  "biscuited"  and  thoroughly 
fused  before  the  application  of  the  additional  lower-fusing  body. 

The  Use  of  a  Lens. — The  use  of  a  3-inch  lens  magnifying 
about  two  diameters,  mounted  on  a  stand  so  that  the  work  can  be 
held  under  it  and  viewed  at  pleasure,  will  prove  of  great  assistance, 
especially  in  the  manipulation  of  the  porcelain  body  in  the  matrix. 

Small  camel's-hair  artist's  brushes  will  be  found  very  service- 
able for  brushing  and  removing  particles  of  the  porcelain  body 


SPECIAL  OPERATIOSS  AXD  ROD  IXLAYS.  335 

around  the  edge  of  the  matrix,  and  at  times  adjusting  small  por- 
tions of  it  in  proper  position. 

Porosity  of  Porcelain. — Porosity  of  porcelain  is  attributable 
to  imperfect  packing,  gassing,  heating  too  quickly,  or  overheat- 
ing. Brittleness  will  result  from  the  same  causes  and  from  cool- 
ing too  rapidly. 

Time=Saving  in  InIay=Work. — Experts  in  the  formation  of 
porcelain  inlays  seldom  use  a  die  or  mold  of  the  cavity  farther 
than  to  assist  in  shaping  the  matrix.  If  time  at  the  operating 
chair  is  to  be  considered,  the  best  plan  in  the  simpler  operations 
of  this  class  is  to  fill  the  matrix  with  wax,  remove  and  invest  (see 
page  369),  then  dismiss  the  patient,  and  have  the  inlay  formed  by 
the  next  appointment. 

Edges  of  Inlays.— In  all  inlays  it  is  preferable  to  have  the 
edges  a  little  too  low  rather  than  too  high.  If  the  porcelain  is  too 
high  it  can  be  ground  down  and  still  give  good  results,  but  the 
original  gloss  is  to  be  preferred. 

Small  Inlays. — Good  edges  are  difficult  to  obtain  in  porcelain 
inlays  smaller  than  a  pin-head  when  made  in  a  matrix.  In  such 
cases  the  use  of  the  porcelain  rod  method  is  preferable. 

Effect  of  Cement  on  Shade. — In  small  labial  inlays,  unless  the 
cavities  are  deep,  the  cement  will  show  through  the  porcelain  in 
such  wise  as  to  mar  the  intended  effect. 

Requirements  in  Inlay=Work. — An  inlay  should  fit  the  cavity 
so  that  the  edges  shall  be  absolutely  exact  and  not  perceptible. 
It  should  not  rock  or  move  when  inserted  in  position,  and  the 
occlusion  should  be  correct.  Slight  rocking  of  an  inlay  when  the 
fusing  is  completed  and  it  is  fitted  in  the  cavity  is  often  occasioned 
by  a  rent  which  existed  in  the  bottom  of  the  matrix,  causing  an 
unevenness  at  that  part.  This  may  be  effectually  corrected  by 
trimming. 

Conservative  Limitations  of  InIay=Work.- — Porcelain  inlays, 
in  the  opinion  of  the  author,  should  be  limited  to  that  class  of 
operations  where  the  question  of  the  exposure  of  a  metallic  filling 
to  be  avoided  is  viewed  from  an  esthetic  rather  than  from  a  prac- 
tical standpoint.  The  advantages  and  durability  of  gold  and 
amalgam  fillings,  as  tooth-savers,  have  been  too  long  and  too 
well  established  to  properly  permit  of  their  supersedure  by  a 
cemented  inlay,  formed  of  an  unyielding  material  like  porcelain, 
except  where  the  question  of  esthetics  is  a  factor.     If  around 


386  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

the  entire  circumference  of  a  porcelain  inlay  when  cemented  in 
the  cavity  there  exists  a  single  point  where  the  adaptation  is  imper- 
fect, that  point  is  vulnerable  with  even  the  best  cements  so  far 
offered  to  the  profession.  A  corresponding  imperfection  in  a 
gold  inlay,  if  formed  according  to  most  recent  methods,  may  be 
remedied  by  the  burnishing  given  its  feather  edge  against  the 
margins  of  the  cavity  before  and  after  cementation  in  the  final 
finishing  of  the  inlay. 


CHAPTER    VIII. 

PORCELAIN     A.ND    PLATINUM    CrOWN-AVoRK. 

STRUCTURAL  REQUIREMENTS— PLATINUM  SOLDER— NATURE  OF  AD 
HESION  OF  PORCELAIN  FUSED  ON  PLATINUM— APPLICATION  OF 
PORCELAIN  BODY  IN  CROWN-WORK— BAKING— DEGREES  OF  HEAT- 
PROCESS  OF  CONSTRUCTION  OF  COLLAR  CROWNS— PARTIAL  COLLAR- 
CAP — BICUSPIDS  AND  MOLARS— PRACTICAL  METHOD  TO  FORM  OC- 
CLUDING SECTION— CROWN  WITHOUT  A  COLLAR  :  LIMITATIONS— 
JACKET-CROWN— INCISORS  AND  CUSPIDS— APPLICATION  OF  THF 
PORCELAIN  VENEER  PROTECTION  OF  INCISAL  EDGE— POK'  E 
LAIN  AND  PLATINUM  BICUSPID  CAP  CROWN  WITH  PORCELAIN  OC- 
CLUDING SURFACE— PORCELAIN  AND  PLATINUM  CROWN  WITH 
METALLIC  OCCLUDING  SURFACE— PORCELAIN  AND  PLATINUM  TUBE- 
CROWN— APPLICATION  TO  CASES  OF  FRACTURED  CROWNS— READY- 
MADE  CROWNS  ON  CAPPED.  ROOTS— LOGAN  CROWN  ON  PLATINUM 
BASE  WITHOUT  A  COLLAR— THE  DAVIS  CROWN  ON  A  CAPPED  ROOT 
—VENEERING  OF  SEAMLESS  GOLD  CROWNS  WITH  PORCELAIN  BY 
THE   AID  OF  LOW-FUSING    PORCELAIN   BODY. 

Porcelain  and  Platinum  Crown-Work. 

Structural  Requirements. — In  porcelain  and  platinum  work, 
the  metallic  structure  constitutes  the  foundation  and  the  porcelain 
the  part  to  be  restored.  The  metallic  part  consequently  should 
be  made  strong  and  rigid  and  of  a  character  that  will  furnish  the 
best  possible  support  and  attachment  for  the  porcelain.  The  line 
of  union  or  joints  of  the  sections  composing  the  metallic  parr 
should  be  closely  fitted  so  as  to  insure  perfect  contact.  Pure  gold 
is  used  ordinarily  as  a  solder  to  unite  the  parts.  Gold  alloyed  with 
the  baser  metals  is  unsuitable,  as  their  presence  would  stain  the 
porcelain.  Only  the  smallest  possible  quantity  of  the  gold  that 
will  effect  the  object  should  be  used,  as  subsequently  in  the  baking 
of  the  porcelain  it  is  entirely  absorbed  by  the  platinum.  Small 
spaces  are  thus  liable  to  be  created  under  the  porcelain  at  points 
which  tend  to  weaken  the  structure  of  the  crown.  In  the  absorp- 
tion of  the  gold,  the  sections  of  the  metal  which  touch  where  it 

387 


388  GROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

was  applied  become  sweated  together  in  such  manner  that  they 
will  not  be  separated  by  any  degree  of  heat  subsequently  applied. 
This  absorption  of  the  gold  solder  consequently  may,  in  a  measure, 
be  effected  at  the  time  of  soldering  by  applying  sufficient  heat. 
This  is  allowable  in  soldering  invested  sections  of  the  metal  alone, 
but  when  porcelain  is  included  the  intense  heat  is  liable  to  cause 
etching  of  the  porcelain  from  its  contact  with  the  investing  mate- 
rials. Etching  may,  in  a  measure,  be  avoided  by  varnishing  the 
surface  of  the  teeth  with  shellac  previous  to  investment. 

Platinum  Solder. — Platinum  solder,  25  per  cent,  platinum  to 
75  per  cent,  gold  (see  Part  V,  Chapter  V),  is  recommended  in 
preference  to  pure  gold,  as  it  is  not  absorbed  in  the  baking  of  the 
porcelain,  and  strengthens  as  well  as  unites  the  parts.  The  com- 
pound oxyhydrogen  blowpipe  flame  is  required  to  fuse  platinum 
solder,  the  use  of  which  is  described  in  Part  V,  Chapter  IV. 

Nature  of  Adhesion  of  Porcelain  Fused  on  Platinum. — 
Porcelain  body  fused  on  platinum  adheres  to  the  surface,  but  the 
adhesion  is  only  mechanical.  Consequently,  should  any  change 
occur  in  the  form  of  the  metallic  base,  the  porcelain  is  liable  to 
become  detached.  This  fact  should  be  kept  in  mind  regarding  this 
class  of  operations.  The  surface  of  the  metal  that  is  to  receive  the 
porcelain  should  be  roughened  or  serrated  with  a  sharp-pointed 
instrument,  and  at  parts  that  suggest  it,  and  where  it  is  permissi- 
ble, either  indented  or  punctured. 

Submitting  the  surface  of  the  platinum  to  the  action  of  aqua- 
regia,  also  sprinkling  coarse  platinum  filings  on  the  surface  of  a 
section  of  the  metal  and  attaching  them  with  an  atom  of  pure 
gold,  furnishes  a  means  of  secure  adhesion  for  porcelain  body.  By 
such  means  quite  a  reliable  attachment  of  the  porcelain  to  the 
metal  is  obtained,  as  is  demonstrated  in  the  construction  of  artifi- 
cial plates  of  porcelain  on  platinum — the  form  termed  continuous- 
gum  work. 

Application  of  Porcelain  Body  in  Crown=Work. — The  me- 
tallic structural  framework  of  the  crown  should  be  thoroughly 
cleansed  of  borax  with  acid  and  washed  free  of  all  particles  of  for- 
eign matter.  Any  sharp  edges  or  points  that  are  liable  to  be  ex- 
posed in  the  finished  crown  are  to  be  rounded  and  smoothed.  The 
method  of  selecting  shades  and  applying  porcelain  body  in  crown- 
work  is  similar  in  principle  to  that  explained  respecting  high-fusing 
body  used  in  inlay-work.    The  porcelain  body  should  be  placed  on 


PORCELAIN  AXD  PLATINUM  CROWX-TVORK. 


389 


a  clean  glass  or  porcelain  slab  and  mixed  with  pure  water  to  a 
dough-like  consistence.  The  addition  of  a  small  quantity  of  dis- 
solved gum  tragacanth  is  used  to  glutinate  the  particles  of  the 
body  in  difficult  contour-work.  The  crown  is  held  by  the  post  in 
a  pin-vise,  as  shown  in  Fig.  698,  during  the  application  of  the 
body.  By  tapping  the  handle  of  the  vise  with  the  mixing  spatula 
as  the  body  is  applied  it  is  packed  into  the  interstices  of  the  work 
and  the  moisture  is  brought  to  the  surface,  to  be  absorbed  with 

Fig.  698. 


blotting  or  bibulous  paper.  More  body  is  then  gradually  added 
until  it  assumes  the  general  form  and  proportions  desired  in  the 
finished  crown.    The  work  is  then  ready  to  receive  the  first  fusing. 

Baking. — The  baking  of  porcelain  body  in  crown-work  is  con- 
ducted as  described  in  Part  IV,  Chapter  III,  "Fusing  of  Porce- 
lain," and  very  similar  to  that  in  "Porcelain  Inlays,"  Part  IV, 
Chapter  VI. 

The  first  bake  should  be  the  "biscuit  bake,"  effected  with  a  heat 


390 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORE. 


which  will  cause  the  body  to  shrink  and  become  hard  but  not 
glazed,  though  the  mass  is  covered  with  shining  particles.  If  the 
work  is  allowed  to  remain  in  the  furnace  for  the  first  baking  until 
the  fusing-point  is  reached,  porosity  and  imperfections  are  liable 
to  appear  in  the  final  application  and  fusing.  After  the  crown  has 
received  the  biscuit  bake  it  may  be  adjusted  in  the  mouth  or  on  the 
articulating  model  and  the  porcelain  ground  off  or  added  to  where 
necessary  for  proper  occlusion  and  approximal  contact. 

For  the  second  bake  the  seams  and  crevices  are  filled  and  the 
body  added  until  the  parts  are  slightly  larger  than  is  required.  As 
in  the  previous  application  of  body,  all  the  moisture  possible  should 
be  brought  to  the  surface  and  absorbed.  The  less  moisture  al- 
lowed to  remain  and  the  greater  the  condensation  of  the  particles 
each  time,  the  less  the  shrinkage  which  will  take  place. 

Fig.  G99. 


For  the  third  or  final  fusing,  after  the  necessary  addition  of 
body  is  made,  the  crown  is  slowly  he"ated  in  the  furnace  and 
allowed  to  remain  until  the  surface  of  the  body  assumes  a  smooth, 
glazed  appearance  corresponding  to  that  of  natural  enamel. 

After  the  final  baking,  the  crown  should  be  allowed  to  cool  very 
slowly  to  temper  the  porcelain.  Too  rapid  cooling  will  injure  the 
crown-work,  if  not  destroy  it.  If  an  electric  furnace  is  used,  the 
current  can  be  turned  off  and  the  work  allowed  to  remain  until 
cool;  or  it  can  be  removed  and  placed  in  a  muffle  provided  for 
cooling  purposes.  When  cool,  the  crown  should  be  dipped  in 
water  before  handling. 

Fig.  699  illustrates  forms  of  fire-clay  supports  on  which  a 
crown  or  bridge  can  be  placed  during  the  fusing  of  the  porcelain. 


PORCELAIN  AND  PLATINUM  CROWN-WORK. 


391 


Degrees  of  Heat. — In  crown-work  the  heat  as  registered  by  the 
pyrometer  for  the  first  bake  should  be  200°  below  the  fusing- 
point  of  the  porcelain  body  used;  that  of  the  second,  or  other 
primary  bakes,  150°,  and  the  final  bake  the  fusing-point.  at  which 
degree  the  crown  should  be  kept  for  twenty  seconds. 


Fl<;.  TOO. 


Fig.  701. 


Porcelain  and  Platinum  Collar  or  Partial  Collar  Crowns. 

Process  of  Construction  of  Collar  Crown — The  collar  should 
be  made  of  platinum,  about  Xo.  29  to  30  gage,  and  the  piece 
which  caps  the  collar  of  about  No.  32  platinum  plate.  The  collar 
or  partial  collar-cap  is  first  constructed  and  fitted  to  the  end  of  the 
root  as  illustrated  in  Figs.  700  and  701, 
according  to  one  of  the  methods  de- 
scribed at  page  132.  The  post  should 
be  substantial,  and  in  all  cases  be  ex- 
tended some  distance  above  the  surface 
of  the  cap  as  an  attachment  for  the 
porcelain.  It  should  be  closely  fitted 
to  the  cap  at  the  orifice  of  the  canal  by 
perforating  the  platinum  and  forcing 
it  to  position  and  then  united  to  the  cap 
with  pure  gold  or,  better,  platinum 
solder.  A  suitable  cross-pin  tooth  is 
selected,  and  ground  and  fitted  on  the 
cap;  a  shade  slightly  darker  than  the 
corresponding  natural  tooth  is  to  be  pre- 
ferred, as  the  color  is  generally  lightened  in  the  baking.  Usually  in 
the  case  of  incisors  and  cuspids  it  will  be  necessary  to  reduce  the 
dimensions  of  the  post  to  permit  it  to  pass  between  the  pins,  and 
in  many  cases  also  to  grind  a  groove  in  the  porcelain  for  its  recep- 
tion. This  is  necessary  to  allow  the  tooth  to  assume  the  proper 
position  on  the  cap,  as  the  bases  of  most  porcelain  fronts  or  teeth 
will  be  found  when  fitted  to  hang  over  the  space  occupied  by  the 
post  in  the  root-canal.  The  pins  should  be  bent  around  the  post  in 
such  manner  as  to  retain  it  in  position  during  the  application  and 
baking  of  the  porcelain:  or.  the  crown  should  be  invested  and  the 
pins  soldered  to  the  post  with  pure  gold,  which  is  generally  the 
better  method  to  pursue.  If  the  end  of  the  post  is  cut  off  nearly 
to  the  surface  of  the  cap  on  account  of  the  occlusion,  the  ends  of 


392 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


the  pins  may  be  slightly  flattened,  and,  when  the  case  is  invested, 
bent  on  the  end  of  the  post  and  substantially  soldered  to  it  with 
platinum  solder.  (See  Fig.  701.)  Should  the  ends  of  the  pins  not 
reach  the  post,  fill  in  with  a  piece  of  plate.  Both  post-end  and 
pins  should  entirely  clear  the  occlusion  of  the  antagonizing  teeth. 
The  crown  when  soldered  is  boiled  in  acid  to  remove  the  flux, 
and  having  been  fitted  on  the  model  or  in  the  mouth  to  determine 
the  accuracy  of  the  parts  and  then  thoroughly  cleansed,  is  ready 
for  the  application  of  the  porcelain  body. 

In  cases  where  the  porcelain  fr*ont  projects,  as  shown  in  gold 
crown-work  in  Fig.  462,  the  part  can  be  filled  with  porcelain. 
Should  the  cervico-labial  section  of  a  collar  be  exposed  to  view,  a 
little  of  the  porcelain  may  be  extended  onto  the  collar  at  that  point 
so  as  to  hide  the  metal,  but  it  should  be  graduated  off  at  the  sides 
toward  the  approximal  spaces. 

Partial  Collar=Cap. — When  a  partial  collar-cap  is  used,  should 
the  cervico-labial  margin  of  the  porcelain  front  extend  perceptibly 
beyond  the  line  of  the  edge  of  the  cap,  the  projecting  portion  of 
the  porcelain  should  be  trimmed  and  re-enameled  in  the  baking. 
Bicuspids  and  Molars. — Bicuspid  and  molar  crowns  can  be 
constructed  in  a  similar  manner  by 
using  a  suitable  facing  on  the  cap, 
and  building  up  the  occluding  sur- 
face and  cusps  with  the  body.  A 
small  additional  post  or  bar,  to  se- 
curely attach  and  support  the  palatal 
cusps,  may  be  added  and  soldered 
to  the  cap,  as  shown  in  the  case  of  a 
bicuspid  in  Fig.  702,  a,  b,  and  c. 

Practical  Method  to  Form  Occluding  Section. — The  length 
of  the  palatal  section  of  the  crown  and  form  of  the  cusps  are 
quickly  and  accurately  determined  by  placing  the  porcelain  body 
— preferably  for  the  first  bake,  foundation  body — of  a  dough-like 
consistence,  in  a  mass  in  position  on  the  cap,  packed  against  the 
facing,  inserting  in  the  mouth,  occluding  the  teeth  on  the  body, 
and  removing.  The  occluding  teeth  in  leaving  their  impression 
on  the  body,  shape  and  outline  the  form  the  occluding  surface 
of  the  crown  should  be.  .  The  porcelain  body  is  then  trimmed  and 
properly  shaped  in  accordance  with  the  form  of  a  natural  crown, 
Fig.  703,  and  then  given  the  biscuit  bake.     More  body  is  again 


PORCELAIX  AXD  PLATINUM  CROWN-WORK.  393 

applied,  guided  by  the  occluding  teeth,  to  compensate  for  the 
shrinkage  and  the  usual  bakes  given.  A,  Fig.  704,  shows  the 
appearance  of  the  crown  after  the  first,  and  B  after  the  final  bake. 

Fig.  703.  Fig.  704. 


Crown  without  a  Collar — A  porcelain  and  platinum  crown 
without  a  collar  is  made  by  fitting  into  the  root  a  substantial  iridio- 
platinum  post,  and  capping  the  root  with  a  disk  of  platinum  as 
described  on  page  129.  A  porcelain  front  is  then  fitted  and 
soldered  to  the  post  as  before  described.  The  disk  of  platinum 
should  be  about  No.  32  gage,  unless  it  is  to  be  removed  after  the 
crown  is  baked;  in  such  a  case  it  should  be  made  about  No.  36 
gage  or  thinner. 

Limitations. — Porcelain  and  platinum  crowns  of  the  forms 
above  described  for  either  the  front  or  back  teeth  are  not  suitable 
for  a  close  occlusion,  or,  as  ordinarily  termed,  a  "close  bite,"  as 
fracture  of  the  porcelain  is  sooner  or  later  quite  certain  to  occur. 
Porcelain  and  gold  construction  in  such  cases  should  be  given  the 
preference  for  incisors  and  cuspids,  and  porcelain  and-  gold  or 
porcelain  reinforced  with  platinum  for  the  bicuspids  and  molars 
constructed  as  further  on  described.  4 

Jacket=Crown — This  crown  combines  the  good  qualities  of 
many  of  the  best  forms.  In  many  cases  it  affords  results  which 
cannot  be  so  well  obtained  by  any  other  method.  It  permits  the 
restoration  by  crown-work  of  a  tooth  without  the  exhibition  of 
metal  at  the  labial  aspect,  and  without  destruction  of  the  pulp. 
It  requires  the  least  possible  removal  of  tooth-structure  to  permit 
the  mounting  of  the  crown.  Its  natural  appearance  admits  of  the 
performance  of  operations  of  a  most  artistic  character. 

"When  the  construction  is  so  conducted  that  the  incisal  edge  is 
protected  with  metal,  it  forms  a  crown  which  for  strength  ap- 
proaches that  of  porcelain  and  gold.  The  post  being  cemented  in 
the  root  independent  of  the  crown  much  simplifies  a  necessary 
reconstruction  of  a  crown. 


394 


CROWN-,  BRIDGE-,  AXD  P0RCELA1X-W0RK. 


Fig.  705.     Fig.  70fi. 


The  jacket-crown  consists  of  a  cone-shaped  platinum  and  porce- 
lain cap  fitted  over  the  natural  crown  or  so  much  of  it  as  remains. 
Incisors  and  Cuspids. — The  crowning  of  a  central  incisor  will 
serve  as  a  typical  case.     Fig.  705  represents 
the  shape  of  the  prepared  tooth.    If  the  crown 
is  broken  off  or  decayed  to  the  gum-margin,  a 
post  is  inserted  in  the  stump  and  shaped  with 
amalgam  to  a  somewhat  conical  form.     A  col- 
lar of  platinum  (No.  30  gage),  the  full  length 
the  crown  is  to  be,  is  made  and  fitted  to  the 
\y  prepared   tooth   or   root.      The   lines   of   the 

palatal  and  labial  surfaces  of  the  adjoining 
teeth  are  marked  on  the  platinum.  The  palatal  portion  of  the  col- 
lar is  cut  away  to  this  line,  so  as  to  clear  the  lower  teeth  in  occlu- 
sion (Fig.  706).  A  piece  of  platinum,  of  the  same  gage,  is  sol- 
dered over  the  collar,  to  form  the  palatal  wall.  The  cap  is  fitted 
in  the  mouth,  and  the  labial  section  of  the  collar  ground  thin 
enough  to  enable  the  platinum  to  be  pressed  and  burnished  against 
the  tooth  or  the  built-up  amalgam.  If  this  cannot  be  done  satis- 
factorily, trim  off  the  platinum  the  same  as  on  the  palatal  side  and 
solder  a  piece  of  platinum  foil  over  the  part  instead.  It  must  be 
remembered  that  in  this  soldering  only  the  least  possible  quantity 
of  pure  gold  should  be  used.  At  this  stage  the  cap  will  assume 
the  form  seen  at  Fig.  707. 

Application  of  the  Porcelain  Veneer. — In  this  style  of  crown 
work  teeth  having  living  pulps  afford  so  limited  a  space  for  the 
porcelain  front  as  not  to  permit  the  use  of 
one  with  pins  for  its  retention  on  the  cap 
during  the  application  of  the  porcelain 
body.  Fronts  can  be  made  of  the  porcelain 
body  alone  for  a  molar  or  second  bicuspid, 
but  the  results  respecting  appearance  would 
be  unsatisfactory  for  the  front  teeth.  Ve- 
neers formed  from  artificial  teeth  are  pre- 
ferably used  for  this  class  of  work  as  a  rule. 

Pulpless  teeth,  and  in  some  cases  those  with  calcification  of  the 
pulp,  will  stand  the  removal  of  sufficient  of  the  natural  crown  to 
allow  of  the  formation  of  a  cap  which  will  permit  the  use  of  a 
front  with  pins  which  can  be  soldered  to  it. 

A  tin' n  veneer  of  porcelain  to  represent  the  tooth  is  made  by 


Fig.  701 


Fig.  708. 


PORCELAIN  AND   PLATINl   \l   CROW  \   WORK.  395 

selecting  an  ordinary  porcelain  tooth  of  the  proper  size  and  shade, 
removing  the  pins  and  grinding  ir  down  as  described  in  Part  V, 
<  hapter  II,  and  illustrated  at  A.  Fig.  707.  The  veneer  is  ground 
and  fitted  to  assume  a  proper  position  on  the  cap.  Porcelain 
body  is  then  applied  and  T 1 1  *  -  veneer  pressed  to  place,  surplus 
moisture  absorbed,  and  particles  of  body  removed.  It  is  possi- 
ble to  tit  the  veneer  held  by  the  body  on  the  cap  in  the  mouth 
when  desirable  The  cap  and  veneer  are  removed  and  placed  on 
silex  on  a  slab,  with  the  face  of  the  veneer  resting  downward  on 
the  silex  to  retain  it  in  position,  and  the  whole  is  then  placed, 
baked,  and  the  body  biscuited.  Another  method  is  to  gently  re- 
move the  veneer  from  the  cap,  disturbing  the  body  us  little  as 
possible,  and  insert  the  cap  without  the  veneer  in  the  furnace. 
When  the  cap  is  baked  the  veneer  will  be  found  to  tit  in  the  inden- 
tation in  the  body.  In  this  way  the  excessive  shrinkage  of  the 
first  baking  and  the  consequent  -light  displacement  of  the  veneer 
are  overcome.  The  veneer  is  then  placed  on  the  cap  with  the 
necessary  body  to  attach  it  and  -lowly  heated  and  baked.  The 
body  should  be  placed  over  and  on  the  incisal  edge  of  the  cap  and 
around  on  the  sides  as  far  as  permissible  to  secure  the  greatesl 
amount  of  attachment  for  the  porcelain. 

After  both  the  first  and  second  bakes  the  work  should  be  fitted 
in  the  mouth  and  any  of  the  changes  incident  to  shrinkage  of  the 
porcelain  body  noted  and  corrected.  Any  necessary  slight  altera- 
tion respecting  the  position  or  size  of  the  veneer  and  the  fused 
applied  porcelain  body  should  also  be  made  at  these  stages  of  the 
construction  so  that  the  porcelain  may  be  enameled  in  the  final 
bake,  which  should  be  mosl  carefully  conducted  in  regard  to 
heating  and  cooling.  After  the  final  bake  the  exposed  surface  of 
the  platinum  should  be  polished.  Crowns  of  this  style  can  only  be 
well  cemented  with  oxyphosphate.  Fig.  708  represents  the  fin- 
ished crown. 

Protection  of  the  Incisal  Edge. — To  protect  the  incisal  edge 
of  a  crown  of  this  style  the  palatal  side  of  the  collar  is  made  of 
iridio-platinum  plate  instead  of  platinum,  of  about  Xo.  30  gage  or 
heavier,  as  the  character  of  the  occlusion  suggests.  The  end  of 
the  strip  is  brought  over  the  incisal  edge  in  a  manner  to  protect 
the  porcelain  in  occlusion,  as  shown  at  P  in  Fig.  709, 1  the  same  as 

1  Dr.  W.  A.  Capon's  method. 

27 


396 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


in  porcelain  and  gold  work.  In  cases  of  jacket-crowns  where  the 
space  will  permit,  a  porcelain  front  may  be  used  with  pins  and  the 
pins  soldered  to  the  cap,  as  shown  in  Fig.  710. 

Porcelain  and  Platinum  Bicuspid  Cap=Cro\vn  with  Porcelain 
Occluding  Surface. — When  the  natural  tooth  is  broken  down  and 
pulpless,  the  following  method  can  be  practiced :  A  platinum 
collar  is  made  and  fitted,  with  the  labial  section  prepared  and  a 
veneer  adjusted  in  the  same  manner  as  in  the  method  just  ex- 
plained. The  edge  of  the  collar  should  clear  the  occluding  teeth 
about  one-thirty-second  of  an  inch.  (See  Fig.  711.)  While  the 
collar  is  in  position,  platinum  foil  is  packed  in,  over,  and  around 
the  end  of  the  root  or  any  part  of  the  natural  tooth  present  (A). 
Porcelain  body  is  then  packed  in  on  the  platinum  foil,  the  space 


Fig.  709. 


Fig.  710.  Fig.  711.        Fig.  712.  Fig.  713. 


being  filled  even  with  the  edge  of  the  collar.  The  veneer  is 
placed  in  position  against  the  porcelain  body  and  the  body  packed 
around  it.  The  crown  is  then  carefully  removed  and  baked. 
After  baking  it  is  placed  in  the  mouth,  the  occlusion  noted,  the 
cusps  properly  shaped  with  body  by  occluding  the  teeth  on  the 
applied  body  as  described  in  relation  to  porcelain  and  platinum 
crowns,  at  page  392,  and  the  final  fusing  of  the  porcelain  performed. 
Fig.  712  illustrates  the  completed  bicuspid  crown.  Fig.  713 
shows  a  molar  constructed  by  this  method.  The  construction 
of  this  crown  may  be  varied  by  soldering  the  foil,  or  a  very 
thin  piece  of  platinum  plate  placed  inside  the  collar,  to  its  sides, 
using  a  porcelain  front  instead  of  a  veneer,  and  soldering  the  pins 
to  the  foil  or  thin  plate.  The  porcelain  forming  the  occluding 
section  being  encompassed  by  the  metal,  develops  great  strength. 
It  is  a  form  of  crown  that  admits  of  extensive  application. 


I'ORCi:i.\I\    AND  PLATINUM   CROWN-WORK. 


397 


A  Porcelain  and  Platinum  Bicuspid  Crown  with  Metallic  Oc= 
eluding  Surface  is  made  as  follows :  The  tooth  or  root  is  prepared 
the  same  as  for  an  all-gold  crown  and  enough  of  the  labial  section 
removed  to  allow  for  the  veneer.  (See  Fig.  714.)  If  badly  broken 
down  it  should  be  built  up  with  a  post  and  amalgam.  (See  page 
40.)  A  collar  of  platinum  is  made  and  fitted  the  same  as  for  an 
all-gold  crown,  and  trimmed  free  of  the  occluding  teeth.  A  suit- 
able grinding-surface  is  made  by  stamping  up  a  piece  of  annealed 
iridio-platinum  plate,  No.  30  gage,  or  heavier,  if  the  case  should 
suggest  it  for  strength.  The  palatal  half  is  soldered  to  the  col- 
lar, but  the  labial  portion  is  left  unsoldered  and  free  (see  Fig.  715), 
to  permit  the  front  portion  of  the  collar  to  be  manipulated.  The 
labial  section  of  the  collar  is  next  ground  thin  and  pressed  in- 
ward against  the  tooth,  to  make  room  for  the  porcelain  veneer. 


Fig.  714. 


Fig.  TIG. 


Fig.   717. 


It  will  then  appear  as  shown  at  Fig.  716.  Puncture  the  thin 
platinum  over  the  labial  surface,  and  select  and  lit  a  porcelain 
veneer  to  represent  the  tooth.  Pack  in  porcelain  body  and  fit  the 
veneer  in  position  in  the  mouth.  Carefully  remove  and  bake  in 
the  furnace.  Next  refit  in  the  mouth,  make  any  necessary 
changes,  add  more  body,  and  give  the  final  baking.  The  platinum 
is  then  polished,  after  which  the  crown  is  ready  to  be  cemented. 
Fig.  717  represents  the  finished  crown. 

The  form  of  crown  just  described  can  be  used  in  bicuspids  in  all 
cases,  more  especially  where  there  is  a  close  occlusion.  In  bridge- 
work,  a  porcelain  front  backed  with  gold  can  be  soldered  to  this 
form  of  crown  to  represent  a  first  bicuspid,  the  precaution  being- 
used  to  heat  and  cool  the  investment  slowly. 

Porcelain  and  Platinum  Tube=Crown. — This  crown  is  for  use 
in  cases  Avhere  the  natural  crown  is  absent  to  the  line  of  the  cervix 
and  a  metallic  collar  is  not  required. 


398  VROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

The  root  is  ground  even  with  the  margin  of  the  gum.  A  How 
or  an  iridio-platinum  post  is  fitted  and  cemented  in  the  root,  as  seen 
in  section  in  Fig.  718,  and,  if  an  excessive  enlargement  of  the  root- 
canal  exists,  amalgam  is  packed  in  the  orifice  of  the  canal  around 
the  post.  In  the  case  of  a  broken  artificial  crown  where  the  post 
remains  with  its  end  protruding  from  the  root,  the  tube  is  to  be 
shaped  to  fit  over  the  post.  Take  a  piece  of  wire,  of  the  gage  of 
the  post,  and  twist  platinum  foil  around  it  so  that  the  foil  shall 
form  a  tube.  Slip  the  tube  on  the  post  in  the  root.  Cut  a  disk  of 
platinum  foil  fully  the  size  of  the  end  of  the  root,  puncture  it  in 
the  center,  and  slip  it  over  the  tube  on  the  post.  Draw  off  tube 
and  disk  carefully,  and  solder  them  together  with  the  smallest 
possible  quantity  of  pure  gold.  This  forms  a  combined  tube  and 
cap.  Adjust  in  the  mouth  and  burnish  the  edges  of  the  platinum 
disk  closely  to  the  root.  Pack  porcelain  body  in  a  thick  paste 
around  the  tube  and  fit  a  veneer  (see  Tig.  718)  in  proper  position 
against  the  body,  remove,  and  bake. 

If  a  porcelain  front  having  pins  can  be  fitted  and  used,  the  pins 
Fig  718  ma^  ^e  s°ldered  to  the  tube  with  a  little  pure  gold  to 
retain  it  in  correct  position  before  the  application  of  the 
porcelain  body;  if  not,  the  use  of  a  veneer  may  be  re- 
sorted to,  the  same  as  in  the  preceding  cases.  After  bak- 
ing, place  the  crown  in  position,  burnish  the  platinum 
thoroughly  at  the  gum  line,  and  trim  off  the  excess.  Add 
body  where  required  and  give  the  final  baking.  It  is 
optional  whether  the  platinum  is  allowed  to  remain  on 
the  base  of  the  crown  or  not,  but  the  portion  at  the 
cervico-labial  section  is  generally  removed  for  the  sake  of 
appearance.  Fig.  718  shows  the  finished  crown  in  section.  Should 
this  crown  fracture  in  use,  it  can  be  replaced  without  disturbing" 
the  post  in  the  root. 

Application  to  Cases  of  Fractured  Crowns. — The  method  just 
described  can  be  applied  at  times  to  advantage  in  the  case  of  an 
incisor  or  cuspid  crown  which  has  been  broken  off,  leaving  its  post 
or  attachment  extending  from  the  end  of  the  root,  and  thus  avoid 
the  occasionally  troublesome  task  of  its  removal. 

Ready=Made  Crowns  on  Capped  Roots — Logan  and  other 
ready-made  porcelain  crowns  may  be  attached  with  porcelain  to 
collar  or  partial  collar-caps.  The  end  of  the  root  is  first 
capped  with  platinum  and  the  root-canal  prepared  to  receive  the 


PORCELAIN  AND   PLATINUM  CROWN-WORK. 


399 


post  of  the  intended  crown.  At  the  palatal  section  of  the  crown 
a  V-shaped  piece  is  removed  sufficient  to  fully  expose  the 
pin  and  base  of  the  crown,  as  shown  in  Fig.  719.  The 
cap  and  crown  are  cemented  with  wax,  removed,  in- 
vested, and  cap  united  to  post  with  a  little  pure  gold. 
The  heating  and  cooling  should  be  done  slowly  to  avoid 
fracture  of  the  porcelain.  The  open  slot  permits  the 
body  to  be  applied  and  the  shrinkage  that  occurs  in  the 
baking  to  be  filled  in  so  as  to  form  a  solid  connection  of 
porcelain  between  cap  and  crown. 

Logan  Crown  on  Platinum  Base  without  a  Collar. — 
A  Logan  crown  without  a  collar  on  a  platinum  base  that 
will  accurately  fit  the  end  of  the  root  can  be  made  with  little 
labor  in  accordance  with  Dr.  Gordon  White's  method,  described 
on  page  137,  and  illustrated  by  Figs.  271  to  275.  In  the  use  of 
porcelain  the  application  of  platinum  foil  to  the  base  of  the  arti- 
ficial crown  is  omitted.  The  disk  of  platinum  fitted  to  the  end  of 
the  root  is  first  soldered  to  the  post  with  pure  gold,  and  porcelain 
body  instead  of  gold  solder  is  then  used  to  fill  in  the  triangular 
space  between  the  root-cap  and  base  of  the  artificial  crown  identi- 
fied with  this  operation. 

The  Davis  Crown  on  a  Capped  Root. — The  Davis  crown  can 
be  quite  advantageously  set  on  a  platinum  cap 
in  the  following  manner:  Cap  the  end  of  the 
root  in  the  same  manner  as  described  on  page  139, 
using  gold  instead  of  platinum  to  form  the  cap, 
and  a  round  iridio-platinum  post  instead  of  the 
Davis  post.  (J rind  and  fit  a  Davis  crown  in 
proper  position  on  cap  with  a  V-shaped  space  cut 
out  of  each  of  the  sides,  as  shown  in  Fig.  720. 
1  liese  spaces  are  for  the  purpose  of  permitting 
the  porcelain  body  to  be  properly  placed  and  baked  around  the 
post  and  between  the  cap  and  crown.  When  the  crown  is  fitted 
to  the  position  it  is  to  assume  on  the  cap,  the  porcelain  should  rest 
on  or  touch  the  cap  at  a  labial  and  a  palatal  point  to  steady  it 
during  the  first  baking  of  the  body. 

To  attach  the  crown  and  cap  together  for  the  first  baking  place 
some  of  the  body  mixed  thin  in  the  post  hole  of  the  crown,  and 
settle  it  to  place  on  the  post  and  cap  and  absorb  the  moisture  with 
bibulous   or  blotting-paper.      At   this   stage   the   crown    may    be 


Fig.  72().  Fig.  721. 


400 


GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


adjusted  in  the  mouth  to  positively  assure  its  correct  alignment. 
It  is  then  carefully  removed  and  baked.  The  heat  applied  should 
only  be  sufficient  to  biscuit  the  body.  It  should  then  be  adjusted 
in  the  mouth  and  any  necessary  trimming  or  polishing  done,  the 
parts  thoroughly  cleaned,  and  the  final  applications  of  body  made. 
Fig.  721  shows  the  finished  crown. 

Veneering  of  Seamless  Gold  Crowns  with  Porcelain  by  the 
Aid  of  Low=Fusing  Porcelain  Body. — Gold  seamless  crowns 
made  of  a  high  grade  of  gold  slightly  alloyed  with  platinum,  such 
as  the  ready-made  "Evans  Crowns,"  can  easily  be  inlaid  and  ve- 
neered with  the  aid  of  the  Jenkins  or  Ash's  low-fusing  porcelain. 
Properly  fit  and  articulate  to  the  tooth  an  Evans  gold  crown,  or  one 
made  seamless  of  gold  slightly  alloyed  with  platinum.     In  some 


Fig.  722. 


Fig.  724. 


Fig.  725. 


cases  this  will  be  facilitated  by  taking  an  impression  of  the  pre- 
pared tooth  in  a  tube  with  plaster,  making  a  fusible-metal  die,  and 
giving  the  gold  crown  the  exact  shape  of  the  tooth,  as  described  on 
page  127,  the  operation  requiring  but  little  time. 

Place  the  crown  when  fitted  on  the  tooth  in  the  mouth,  with  a 
sharp  instrument  mark  the  labial  portion  of  the  gold  which  is 
exposed  to  view,  and  remove  the  crown.  Place  in  the  interior  of 
the  crown  a  mixture  of  plaster  prepared  to  set  quickly,  adjust  it 
in  the  mouth,  occlude  the  teeth,  and  when  the  plaster  is  set  re- 
move the  crown.  In  the  interior  will  be  found  an  exact  impres- 
sion of  the  portion  of  the  natural  tooth  which  is  to  be  capped. 

To  Form  an  Impromptu  Die. — Taper  and  slightly  notch  the 
point  of  a  pieee  of  orange-wood.  Warm  the  point  of  the  wood 
and  press  around  it  a  small  piece  of  Ash  &  Sons'  Dental  Lac,  or 


PORCELAIN  AND  PLATINl   1/   CROWN-WORK.  401 

of  impression-compound,  shaped  to  a  point.  Wet  the  plaster  in 
tin-  interior  of  the  crown,  press  in  the  lac  or  compound,  and  press 
the  stick  through  it  into  the  center  of  the  crown,  as  shown  in  Fig. 
722,  chill  with  water,  and  remove.  In  this  way  a  die  is  quickly 
made,  as  illustrated  in  Fig.  723,  duplicating  the  form  of  the 
prepared  natural  crown.     The  patient  can  then  be  dismissed. 

The  plaster  in  the  crown  is  next  softened  and  easily  removed  by 
heating  the  crown  and  dipping  it  in  water.  The  portion  of  the 
labial  section  of  the  gold  crown  that  was  marked  in  the  mouth 
is  thinned  to  about  1/500  of  an  inch  with  a  small  corundum-disk. 
The  narrow  strip  of  the  collar  at  the  cervico-labial  portion  which 
fits  under  the  gum  is  left  intact,  as  shown  in  Fig.  724.  The 
thinned  section  of  the  gold  is  punctured  in  three  places.  The 
crown  is  placed  on  the  die  and  the  thinned  gold  is  slit  across  the 
line  of  the  occluding  surface  (C,  Fig.  724),  and  then  pressed  in 
against  the  surface  of  the  die,  as  shown  at  B,  Fig.  725,  to  obtain 
depth  and  strength  for  the  porcelain.  The  natural  tooth  must  be 
previously  trimmed  to  permit  this  allowance. 

Prepare  a  porcelain  veneer  (see  Part  V,  Chapter  II),  and  lit 
it  to  the  labial  face  of  the  crown. 

The  porcelain  body  is  next  applied  as  follows:1  The  body  is 
moistened  with  water  to  a  doughdike  consistence.  A  portion  is 
placed  in  the  interior  of  the  crown  just  as  the  plaster  was,  the 
crown  is  pressed  on  the  die,  the  body  which  protrudes  at  tin; 
labial  section  is  compressed,  the  veneer  pressed  to  place,  and  the 
surplus  body  removed.  The  die  is  then  carefully  removed.  In 
the  interior  of  the  crown  will  be  found  an  exact  impression  of  the 
natural  tooth.  Any  loose  particles  of  body  are  gently  removed 
with  a  camel's-hair  brush,  and  the  crown  is  placed  on  a  tray  filled 
with  asbestos,  the  veneer  face  upward,  and  given  a  biscuit  bake 
(Fig.  726).  In  the  baking  the  porcelain  shrinks  so  that  an  easy 
adjustment  of  the  crown  on  the  die  is  insured,  and  some  space  is 
left  for  cement  when  finished. 

The  porcelain  in  the  interior  will  usually  show  some  imper- 
fections caused  by  shrinkage.  Those  of  a  trifling  character  need 
not  be  considered,  but  if  they  are  extensive  a  little  body  should  be 
applied  to  the  part  and  the  die  inserted  to  compress  and  shape  it. 
Application  of  body  is  likewise  made  to  imperfections  on  the  ex- 

1  The  Jenkins  New  Prosthetic  Porcelain  is  specially  suitable  for  this  work. 


402 


CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 


terior  of  the  crown  around  the  veneer,  and  it  is  again  baked. 
For  the  finish,  body  is  applied  only  to  imperfections  on  the  exterior 
of  the  crown,  and  it  is  then  given  the  third  or  final  fusing. 

When  the  crown  is  finished,  should  any  part  of  the  interior 
obstruct  perfect  adjustment,  the  exact  spot  can  easily  be  dis- 
covered by  the  application  of  a  little  rouge  moistened  with  oil, 
either  to  the  inside  of  the  crown  or  to  the  surface  of  the  tooth, 
and  inserting  the  crown  in  the  mouth.  The  obstructing  spot  will 
be  marked  on  the  crown  or  tooth,  according  to  which  the  rouge 
was  applied. 

In  the  form  of  crown  just  described  the  porcelain,  as  illustrated 
at  P  B,  Fig.  727,  fills  all  the  interior  of  the  grinding-surface  not 
occupied  by  the  end  of  the  natural  tooth,  and  is  joined  to  the 
porcelain  front,  V,  which  it  anchors  and  secures.  If  the  gold  is 
worn  away  by  the  occluding  teeth  it  only  exposes  the  porcelain. 


Fig.  72G. 


Fig. 


It  will  be  noticed  also  that  the  greatest  thickness  of  porcelain 
exists  at  the  point  of  union  (P  B)  between  the  section  in  the 
grinding-surface  and  that  at  the  labial  forming  the  front  where 
the  most  strength  is  required. 

Under  favorable  circumstances  this  method  permits  the  easy 
performance  of  artistic  operations  in  crown-work,  but  it  is  not 
suitable  to  apply  in  close  "bites"  or  where  the  occluding  teeth 
antagonize  outside  of  the  normal  line. 

Where  a  porcelain  veneer  is  used  in  connection  with  a  low- 
fusing  body,  there  is  not  so  much  danger  of  changing  its  shade 
by  repeated  bakings,  as  with  a  higher-fusing  body. 

A  seamless  platinum  crown  can  be  inlaid  in  a  similar  manner 
with  high-fusing  porcelain  body.  Platinum  imparts  to  the  mar- 
gins of  the  inlay  a  less  agreeable  shade  than  gold. 

With  high-  and  low-fusing  porcelain  on  hand,  and  proper  means 
of  fusing,  an  ingenious  dentist  can  find  a  multitude  of  ways  to 
use  both  grades  to  practical  advantage. 


CHAPTER    IX. 

Porcelain  Bridge-Work. 

character— limitations— structural  requirements— process  of 
construction— cases  of  porcelain  bridge-work. 

Character. — Porcelain  bridge-work  consists  of  a  base  or  frame- 
work of  platinum  covered  with  porcelain,  which  is  fused  to  it. 
Owing  to  the  unalterable  character  and  continuity  of  its  surface, 
and  the  incorruptibility  of  the  material,  it  has  advantages  as 
a  denture  when  permanently  inserted.  In  comparison  with  gold 
work  it<  construction  is  less  laborious,  but  its  insertion  and  attach- 
ment to  the  abutments  are  a  more  complex  operation. 

Limitations. — In  practical  application  the  scope  of  porcelain 
bridge-work  is  limited.  This  is  owing  to  the  form  of  pier  supports 
required  and  to  the  fact  that  the  occluding  surfaces  of  the  teeth 
forming  the  bridge  are  not — neither  can  they  very  well  be — 
formed  of  or  protected  with  metal,  as  in  a  case  of  combined  sol- 
dered gold  and  porcelain  work.  In  close  bites  and  where  great 
force  is  exercised  in  occlusion,  or  where  the  bridge  is  of  great 
length,  unprotected  porcelain  is  unequal  to  the  strain. 

Structural  Requirements. — In  porcelain  bridge-work  the  metal 
structural  frame  should  be  calculated  on  as  constituting  the 
strength  of  the  bridge.  It  should  be  formed  so  as  to  interfere 
with  the  continuity  of  the  structure  of  the  porcelain  in  the  least 
possible  degree.  By  such  an  arrangement  of  the  metallic  section 
the  greatest  degree  of  strength  is  developed  in  the  porcelain. 

Figs.  728  and  729  represent  an  improper,  and  Figs.  730  and 
731  the  proper,  placing  of  the  bar  in  a  tooth  and  in  a  bridge  in 
porcelain-work.  In  Fig.  728  the  continuity  of  the  porcelain  is 
broken  by  the  presence  of  the  bar  in  the  center.  Fig.  730  shows 
the  bar  at  the  base  united  to  a  cap  or  saddle.  The  bar  as  shown 
in  Fig.  731,  united  to  the  caps  and  saddle,  affords  far  greater 
strength  and  rigidity  than  either  would  separately,  as  illustrated 

403 


404 


CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 


in  Fig.  729,  largely  through  avoiding  interruption  of  the  con- 
tinuity of  the  structure  of  the  porcelain. 

The  metal  portion  of  the  bridge,  consisting  of  the  caps  on  the 
piers  and  the  metal  spanning  the  space  between  the  abutments, 
must  be  so  solidly  united,  rigid,  and  strong,  as  to  provide  inde- 
pendently of  the  porcelain  the  necessary  strength  for  the  structure. 
Should  a  platinum  crown  be  used  on  one  of  the  piers,  the  end  of 


Fig.  728. 


Fig.  729 


Fig.  731. 


the  bar  must  be  flattened  and  extended  well  around  on  the  palatal 
side  of  the  crown,  and  securely  attached  with  platinum  solder. 

Porcelain  bridge-work  is  now  almofet  universally  constructed 
with  the  teeth  forming  the  bridge  resting  on  a  metal  plate  or 
saddle  of  the  width  of  their  bases.  In  a  case  where  a  saddle  is 
not  used,  a  heavy  triangular  or  half-round  bar  (A,  Fig.  732)  of 


Fig 


Fig.  733. 


iridio-platinum,  in  connection  with  a  flattened  cross  and  upright 
bar,  as  shown  in  Figs.  732  and  733,  may  be  used.1  This  latter 
style  leaves  a  self -cleansing  space  under  the  bridge,  which  is  not  as 
desirable  as  a  saddle,  especially  for  upper  cases  of  porcelain  bridge- 
work.  The  contour  of  the  palatal  side  in  the  saddle  form  is  more 
agreeable  to  the  patient,  and  experience  shows  that  in  most  cases, 
where  details  of  construction  have  been  properly  carried  out,  it  is 


1  Dr.  H.  J.  Goslee's  method. 


PORCELAIN    BRIDGE-WORK.  405 

more  cleanly.  Experience  also  shows  that  the  percentage  of  cases 
in  which  absorption  of  the  alveolar  ridge  takes  place  to  any  great 
extent  is  so  small  as  not  to  be  considered,  in  view  of  the  advan- 
tages that  are  otherwise  obtained. 

Process  of  Construction.— The  case  illustrated  in  Fig.  734  is 
presented  as  typical,  to  illustrate  the  construction  of  a  piece  of 
porcelain  bridge-work.  The  cuspid  and  molar  roots  are  capped 
with  platinum,  and  iridio-platinum  posts  inserted,  that  of  the  molar 
cap  in  the  palatal  root.  The  caps  and  posts  are  to  be  soldered  with 
25  per  cent,  platinum  solder.  An  impression  is  taken  of  the 
alveolar  ridge,  a  model  and  metal  model  made,  and  a  platinum 
saddle  struck  up  to  span  the  space  and  accurately  meet  the  crowns. 
The  platinum  is  cut  to  the  length  of  the  combined  bases  of  the  arti- 
ficial teeth  which  are  to  rest  upon  it.     The  caps  are  placed  in  the 

Fig.  734. 


mouth,  the  saddle  in  position  between  the  caps,  and  an  impression 
is  taken,  and  the  caps  withdrawn  in  position  in  the  impression. 
In  taking  the  impression,  pressure  should  be  exerted  on  the  saddle 
during  the  setting  of  the  plaster  through  a  slot  in  the  impression- 
tray.  The  impression  with  the  saddle  in  position  is  filled  with  a 
mixture  composed  of  two  parts  plaster,  two  parts  shredded  asbes- 
tos, and  one  part  calcined  marble-dust,  to  form  a  model.  On  the 
removal  of  the  plaster  impression,  the  platinum  saddle  with  the 
crowns  will  be  found  in  position  on  the  model. 

An  iridio-platinum  cross-bar,  made  of  No.  14  gage  round  wire 
rolled  to  No.  16  gage  and  set  on  edge,  is  extended  from  the 
post  of  one  cap  to  the  post  of  the  other,  fitting  closely  against  or 
on  the  posts,  and  resting  on  the  caps  and  saddle.  (See  Fig.  734.) 
The  saddle  is  next  soldered  to  the  caps,  and  the  cross-bar  to  the 
caps  and  saddle,  with  25  per  cent,  platinum  solder.  To  retain 
the  bar  in  position  on  the  caps,  a  little  investing  material  should 
be  placed  crosswise  over  the  bar  in  the  center  of  the  investment; 


40G  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

as  soon  as  the  saddle  and  the  ends  of  the  bar  are  soldered,  this  little 
piece  of  investment  is  removed  and  the  soldering  of  the  bar  com- 
pleted. This  framework  makes  a  metal  structural  foundation 
for  the  bridge,  the  strength  and  rigidity  of  which  will  not  be  im- 
paired in  fusing  on  the  porcelain  body.  Body  such  as  "Close's" 
fuses  at  a  temperature  which  will  not  melt  a  grade  of  platinum 
solder  above  20  per  cent,  The  piece  is  next  adjusted  in  the 
mouth,  the  caps  held  solidly  in  position,  and  the  platinum  pressed 
and  burnished  against  the  tissues  at  any  spots  that  seem  to  suggest 
it,  and  at  the  edges,  sufficiently  to  make  a  white  line  at  the  margin, 
but  not  enough  to  cut  into  the  tissues.  This  is  done,  not  for  the 
purpose  of  obtaining  alveolar  support,  but  for  the  exclusion  of 
particles  of  food  from  under  the  bridge,  a  condition  that  is  main- 
tained even  though  slight  absorption  of  the  membrane  should 
supervene.  Impression-compound  is  next  placed  on  the  bridge 
and  an  impression  of  the  occluding  teeth  taken,  and  the  bridge 
with  the  compound  removed.  Next  the  interior  of  the  caps  and 
surface  of  the  pins  are  coated  with  wax  to  render  removal  easy, 
and  plaster  articulating  models  are  made.  Facings,  or  suitable 
teeth  with  long  pins,  are  selected  and  the  under  side  of  the  pins 
ground  flat,  to  present  a  larger  surface  of  contact  to  the  bar. 
The  facings  are  ground,  fitted,  waxed  in  position,  the  bridge- 
work  removed  from  the  model,  and  invested  in  plaster  and 
asbestos.  The  wax  is  removed,  each  pin  is  bent  down  in  close 
contact  with  the  bar,  and  soldered  to  it  with  the  least  possible 
quantity  of  pure  gold;  the  case  is  then  removed  and  boiled  in 
acid.  Pure  gold  is  used  for  this  soldering,  as  the  heat  required 
to  flow  platinum  solder  would  be  liable  to  etch  the  invested 
porcelain  teeth.  Fig.  734  shows  the  appearance  of  the  bridge  at 
this  stage  of  the  construction. 

Porcelain  body  such  as  is  used  in  continuous-gum  work  is  ap- 
plied in  a  similar  manner  to  the  case.  Interstices  are  filled,  grind- 
ing-surfaces  and  cusps  which  are  to  be  formed  are  built  up  and 
contoured  as  much  as  possible  for  the  first  baking.  For  the  next 
baking  more  body  is  added,  shrinkage  being  allowed  for  and 
remedied.  More  than  three  bakings  are  seldom  necessary.  The 
heat  should  be  sufficient  to  thoroughly  fuse  the  body,  give  a 
glazed  surface,  and  develop  the  strength  of  the  porcelain.  Fig. 
735  illustrates  the  bridge  ready  for  cementation. 

A  case  of  porcelain  bridge-work,  such  as  has  been  described, 


PORCELAIS    BRIDGE-M  ORK. 


407 


is    best    cemented    with    gutta-percha.      (See    Part    II,    Chapter 
XVII.) 

Cases  of  Porcelain  Bridge=Work. — Fig.  73G  represents  a 
porcelain  extension  bridge  in  which  the  support  consists  of  a 
crown  and  bar  combined. 


Kir;.   735. 


In  porcelain  bridge-work  artificial  gum  to  a  moderate  amount 
can  be  formed  above  the  teeth  of  the  bridge. 

Fig.  737  is  a  lower  bridge  firmly  supported  on  the  right  side  by 


Fig.  737. 


passing  the  bar  through  the  cuspid  and  inserting  the  end  in  the 
pulpless  bicuspid  as  illustrated.  The  pulpless  bicuspid  on  the  left 
constitutes  the  other  abutment.  The  absorption  of  the  alveolar 
process  was  replaced  with  gum-enameled  porcelain. 


PART    V. 


MATERIALS  AND  PROCESSES  USED  IN  CROWN- 
AND  BRIDGE-WORK. 


FAKT    V. 

c  II  A  I'T  E  R    I. 
I  *i  a.tes  ami  Soldi  rs. 

PLATINUM  —PLATINUM  FOIL  AND  WIRE— PLATINUM  AM'  GOLD  COLLAR 
IRIDIUM— GOLD— GOLD      ALLOYS      FOR      PLATE— GOLD      PLATINUM- 
LINED  PLATE    -PLATINIZED  GOLD— MELTING  AND  REPINING  <'I    GOLD 
SCRAPS— GOLD    SOLDEKS      BARD-FLOWING    GOLD    SOLDER— FLUXED 
SOLDER    FILINGS— SILVER    SOLDER— PLATINUM    SOLDER— FLUX. 

I.\  the  construction  of  crown-  and  bridge-work,  gold,  platinum, 
and  iridio-platinum  arc  used  pure  and  alloyed  in  various  forms  as 
best  suit  the  requirements  of  the  work  and  the  preference  of  the 
dentist. 

Platinum. — Platinum  retains  its  color  and  resists  the  action  of 
the  secretions  of  the  mouth  better  than  pure  gold.  For  this 
reason  and  also  because  of  its  physical  properties  respecting  malle- 
ability and  ductility,  as  well  as  its  extreme  high  fusing-point 
when  formed  in  any  gage  of  plate  or  foil,  it  make-  a  very  useful 
material  in  many  part-  of  the  work.  Platinum  is  valuable  as  an 
alloy  to  raise  the  melting-point  of  gold  plate  and  increase  its 
tensility. 

Platinum  plate  Xos.  29  to  30  gage  is  used  for  forming  seamless 
crowns  for  porcelain  work,  and  from  Xos.  30  to  32  gage  for  collars 
for  crowns. 

Platinum  Foil  and  Wire.- — Platinum  in  the  form  of  thin  plate 
from  Xo.  31  gage  to  that  of  foil,  and  wire  at  from  Xo.  21  to  Xo.  16 
gage,  is  used  in  various  operations  associated  with  the  work. 

Platinum  foil  can  be  made  exceedingly  thin  by  first  rolling- 
down  to  about  1/1000  of  an  inch,  then  oiling  the  surface,  folding 
evenly,  and  again  rolling  down.  By  this  method  the  metal  is 
less  liable  to  crack. 

Platinum  and  Gold  Collar. — In  some  cases  platinum  can  be 
utilized  for  this  purpose  to  advantage  at  from  Xos.  33  to  34  gage. 
The  collar  when  fitted  can  be  stiffened  by  the  addition  of  pure 
gold  flowed  over  its  outer  surface  after  placing  investing  material, 
moldine,  whiting,  or  dampened  fine  calcined  marble-dust  in  the 
interior. 

28  411 


412  CROWN-,  BRIDGE-,  AND  PORCELAIN AVORK. 

Iridium. — Iridium  is  used  as  an  alloy  for  platinum,  to  which  it 
imparts  hardness  and  elasticity. 

Iridio-platinum  wire  is  used  for  pivots  or  posts  when  greater 
rigidity  is  required  than  is  possessed  by  pure  platinum. 

Gold — Gold  plate,  24  carats,  from  No.  28  to  No.  30  gage,  is 
generally  used  for  backing  porcelain  teeth  and  forming  collars 
and  caps  where  great  flexibility  of  metal  is  required. 

Gold  plate,  slightly  alloyed, — about  23  carats  fine, — in  crown- 
work,  if  less  flexibility  of  the  metal  is  required. 

Gold  plate,  22  carats,  No.  28  to  No.  30  gage,  in  constructing 
collars  for  crowns  with  porcelain  fronts,  all-gold  crowns  made  in 
sections,  and  seamless  crowns. 

Gold  plate,  20  carats,  in  construction  of  bridge-work. 

Gold  for  constructing  collars  should  be  of  as  high  a  carat  as 
possible,  to  better  resist  the  action  of  acids.  A  large  proportion 
of  copper  as  an  alloy  is  objectionable,  owing  to  its  tendency  to 
cause  tarnishing  of  the  collar  where  an  acid  condition  of  the 
mouth  exists.  For  this  reason,  United  States  gold  coin,  contain- 
ing 10  per  cent,  copper,  to  some  extent  used  for  collars,  is  not 
suitable.  It  is  also  too  stiff,  and  collars  made  of  it  are  not  readily 
burnished  to  fit  at  the  edges.  Formulas  with  a  less  proportion  of 
copper  are  decidedly  preferable. 

Gold  Alloys  for  Plate. — An  alloy  of  one  part  of  coin  and  two 
parts  pure  gold  is  recommended  for  crowns  constructed  in  sec- 
tions, and  one  part  coin  to  three  of  pure  gold,  as  being  more 
flexible,  for  seamless  crowns. 

The  high  color  of  these  two  alloys  can  be  modified  by  reducing 
the  quantity  of  pure  gold,  substituting  in  its  place  a  percentage  of 
pure  silver,  as  follows : 

For  crowns  constructed  in  sections : 

Coin  gold,     5  dvvt. 
Pure  gold,     9     " 
Pure  silver,  1     " 


For  seamless  crowns 


Coin  gold,     5  dvvt. 
Pure  gold,  13*  " 
Pure  silver,  lb  " 


PLATES  AND  SOLDERS.  413 

A  formula  for  plate  of  the  character  of  clasp-metal  for  stiff- 
ness is : 

Pure  gold,  10  parts. 
Copper.         2      " 
Silver,  1  part. 

Platinum.     1       " 

A  slight  increase  in  the  proportion  of  copper  and  platinum  will 
be  productive  of  an  increase  of  hardness  and  stiffness  of  the  plate. 

Gold  PIatinum=Lined  Plate. — Gold  plate,  24  carats,  with  a 
lining  of  platinum,  can  be  used  in  any  of  the  processess  of  crown- 
and  bridge-work,  and  is  recommended  to  the  inexperienced,  be- 
cause  the  melting  of  a  part  of  a  crown  in  the  soldering  process  is 
less  liable  to  occur  by  its  use.  It  is  formed  by  placing  together 
an  annealed  gold  plate  and  a  platinum  plate  (the  gold  about  No. 
20  gage  and  the  platinum  No.  30)  and  passing  them  through  a 
rolling-mill,  in  which  process  the  plates  arc  welded  and  reduced 
to  the  desired  thickness.  In  soldering  the  seam  of  union  of  a 
collar  the  two  ends  of  the  metal  require  to  be  clamped  together 
until  united  by  the  solder,  as  the  unequal  expansion  of  the  gold 
and  platinum  will  spring  them  apart  and  open  the  seam. 

Platinized  Gold. — An  alloy  of  pure  gold  and  2  to  3  per  cent, 
platinum  can  be  used  to  advantage  in  various  operations.  Gold  so 
alloyed  is  but  slightly  affected  in  color,  ^nd  is  very  flexible.  A- 
plate  it  can  be  used  exceedingly  thin  with  much  less  liability  to 
being  melted  than  pure  gold. 

Melting  and  Refining  of  Gold  Scraps. — The  conversion  of 
gold  scraps  into  plate  is  worthy  of  practice  from  an  economical 
standpoint. 

Passing  a  magnet  through  scraps  or  filings  will  remove  particles 
of  iron. 

A  moderate  quantity  of  clean  scraps,  using  plenty  of  borax, 
can  be  melted  with  a  gas  blowpipe  and  allowed  to  cool  in  a  depres- 
sion of  a  soldering-block. 

For  a  large  quantity  use  a  small  crucible  well  lined  with  borax 
and  fuse  in  a  gas  or  charcoal  furnace  and  pour  into  a  warm  ingot- 
mold.  The  gold  should  be  allowed  to  cool  slowly  and  should  never 
be  removed  from  the  ingot-mold  and  immersed  in  water  while  still 
hot. 

When  cool  it  should  be  boiled  in  acid,  cleaned,  hammered  out, 
annealed,  and  rolled  in  a  mill  to  the  desired  gage. 


414  CROWN-,  BRIDGE-,  AND  PORCELAIN -WORK. 

Should  the  scraps  contain  particles  of  solder  they  can  be  refined 
by  the  dry  process. 

This  consists  in  placing  the  scraps  in  a  crucible  lined  with 
borax,  fusing  at  a  high  heat  for  a  considerable  time,  and  applying 
nitrate  of  potash  (saltpetre). 

Gold  Solders. — The  matter  of  solder  respecting  its  grade  and 
character  is  important  in  crown-  and  bridge-work  operations.  In 
fineness  it  should  approach  that  of  the  plate  used,  should  exhibit 
strength  and  elasticity  when  in  plate  form,  and  melt  and  flow 
smoothly  under  the  properly  applied  heat  of  the  blowpipe.  The 
production  of  solder  of  uniform  quality  requires  knowledge  and 
skill  only  possessed  by  those  constantly  engaged  in  its  manufac- 
ture. For  this  reason,  although  some  operators  alloy  and  make 
their  plate  and  remelt  their  scraps,  very  few  prepare  solder,  pre- 
ferring to  purchase  it.  As  purchased,  the  name  18-  or  20-carat 
solder  does  not  imply  that  the  solder  will  assay  18  or  20  carats 
fine,  respectively,  but  that  the  figures  give  the  grade  of  plate  it  is 
intended  for. 

18-  and  20-carat  solders  are  used  for  crowns  and  bridges,  though 
some  consider  18  carat  too  low  for  the  purpose. 

22-carat  solder  is  seldom  used  except  on  the  exposed  outside 
surface  of  a  gold  crown. 

14-carat  solder  is  used  only  in  filling  the  cusps  of  seamless 
crowns  in  single  crowning  operations. 

Solder  is  made  by  some  by  alloying  the  same  grade  of  plate 
upon  which  the  solder  is  to  be  melted.  For  such  alloy  a  soft 
quality  of  fine  brass  wire  is  the  best.  Spelter  solder  is  also  used. 
The  following  formula  is  an  example : 


22-carat  plate,  4  dwt. 

Fine   brass    wire.    12  grains. 


Allowing  for  the  alloy  already  present  in  the '22-carat  plate, 
the  result  is  a  solder  about  19^  carats  fine.  A  smaller  proportion 
of  alloy  added  to  the  22-carat  plate  will  give  a  corresponding 
result;  for  instance,  2  grains  to  each  dwt.  will  produce  a  solder 
about  20 i  carats  fine. 

Dr.  W.  H.  Dorrance  recommends  the  following  formula  as  an 
alloy  for  the  formation  of  different  grades  of  gold  solders,  the 


PLATES  AND  SOLDERS.  415 

proportion  of  the  alloy  used  determining  the  melting-point  and 
fineness  in  carat  of  the  solder : 

Pure  silver,  1  part. 
Pure  zinc,  2  parts. 
Pure  copper.  3      " 

The  silver  and  copper  are  first  melted  together  in  a  crucible 
lined  with  borax,  and  the  zinc  added  quickly  in  small  pieces, 
stirring  the  mass  meantime  with  a  clay  pipe-stem.  It  is  then,  on 
the  fumes  of  the  zinc  passing  off,  immediately  poured  into  an 
ingot-mold  or  into  a  large  wooden  pail  filled  with  water;  4  grains 
of  this  alloy  melted  with  20  grains  of  pure  gold  will  result  in  a 
solder  fully  20  carats  fine. 

Hard=Flo\ving  Gold  Solder. — This  grade  of  solder  is  for  use  in 
crown-  and  bridge-work.  It  is  conveniently  made  by  melting 
together,  by  weight,  one-third  18-carat  solder  to  two-thirds  18- 
carat  gold  plate;  20-carat  solder  and  plate  can  be  used  in  the  same 
proportion  to  form  a  higher  grade.  The  plate  is  first  melted  and 
the  solder  then  added,  and  when  cooled  rolled  out  to  the  desired 
gage.' 

Fluxed  Solder  Filings. — Fluxed  gold  solder  filings  are  made 
by  filing  with  a  clean,  flat  plate-file  a  thick  piece  of  solder  held 
in  a  vise.  The  filings  are  allowed  to  fall  into  a  box  or  on  a  sheet 
of  paper  placed  to  receive  them.  A  magnet  should  be  passed 
through  the  filings  to  remove  any  minute  particles  of  steel.  To 
five  parts  of  the  filings  so  made  is  added  and  well  mixed  with 
them  one  part  of  the  prepared  flux  or  finely  pulverized  vitrified 
borax.  Solder  prepared  in  this  way  is  useful  for  strengthening 
crowns,  and  also  in  fine  soldering  operations,  as  the  particles  of 
the  solder  take  the  heat  separately  and  fuse  much  more  quickly 
than  when  the  solder  is  cut  in  pieces.  The  flow  of  the  solder  is 
also  more  easily  limited. 

Silver  Solder. — Silver  solder  is  frequently  used  by  the  student 
and  practitioner  in  the  construction  of  experimental  or  specimen 
work  in  connection  with  coin  silver,  nickel,  or  German  silver. 

A  reliable  formula  is : 

Coin  silver,  90  parts. 
Zinc,  10      " 

1  This  formula  is  the  one  used  by  the  author,  and  is  convenient  and  re- 
liable. 


416  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Platinum  Solder.- — Platinum  solder  is  made  by  alloying  pure 
gold  with  from  15  to  30  per  cent,  of  platinum.  It  is  used  to 
unite  the  platinum  sectional  framework  of  a  crown  or  bridge  for 
porcelain-work.  The  grade  of  solder  is  determined  by  the  fusing- 
point  of  the  porcelain  used. 

Flux. — Borax  is  the  preferred  flux  for  soldering  dental  work. 
For  small  fine  soldering  and  deeply  invested  sections  it  should 
be  ground  with  water  on  a  slab  and  applied  with  a  fine  camel's- 
hair  brush  before  heating  the  metal  or  investment.  For  applica- 
tion during  soldering  it  should  be  first  vitrified  and  then  ground 
to  a  fine  powder.1  Vitrification  divests  borax  of  its  water  of 
crystallization,  and  in  this  vitrified  form  it  can  be  sprinkled  on  the 
metallic  sectional  parts  of  the  work  and  fused  without  disturbing 
their  position  through  expansion,  which  is  liable  to  occur  when 
ordinary  pulverized  borax  is  used.  Preparations  of  borax  should 
be  kept  perfectly  clean,  as  the  invasion  of  foreign  matter  will 
cause  pits  in  the  solder.  Jeweler's  liquid  flux  is  used  to  some 
extent  in  place  of  ground  borax. 

The  object  of  flux  is  to  prevent  oxidation  of  the  metal  when 
heated  and  thus  enable  the  portion  which  is  fused  to  flow  more 
freely  and  unite  better  with  the  surface  of  the  higher  fusing 
metal.  The  lower  grades  of  alloys  require  more  flux  than  the 
higher,  as  is  evidenced  in  the  soldering  of  platinum  with  pure 
gold.  The  quantity  of  flux  applied  to  work  during  the  soldering 
should  be  limited  to  the  least  which  will  accomplish  the  object  of 
its  use,  as  an  excess  by  its  presence  obstructs  the  control  and  addi- 
tion of  solder,  and  is  liable  to  reach  and  damage  the  porcelain  by 
fusing  upon  its  surface. 

1  Dr.  Parr's  "Prepared  Flux,"  a  finely  pulverized  vitrified  flux,  can  be  used 
in  this  manner.  It  is  also  prepared  in  combination  with  wax  cement.  In 
the  melting  out  of  the  wax  when  the  case  is  invested  and  heated  for  soldering, 
the  flux  is  carried  into  the  interstices. 


CHAPTER    II. 

Poecelabs  Teeth, 
essentials— fractures,  causes  op— veneers. 

Essentials. — The  qualities  requisite  in  porcelain  tooth  body 
for  use  in  crown-  and  l>ridge-work  are  density,  strength,  and  the 
ability  to  withstand  unaltered  in  form  or  shade  anv  decree  of  heat 
to  which  they  may  necessarily  be  subjected.  In  these  respects 
the  porcelain  tooth  of  our  host  American  manufacture  seem  to 
exec],  besides  affording  the  most  artistic  imitation  of  the  natural 
teeth  in  form  and  shade.  They  are  also  distinguished  by  the 
practical  location  of  the  pins. 

In  some  crowning  operations,  where  to  imitate  the  conforms 
tion  of  a  natural  crown  considerable  alteration  of  the  labial  sur- 
face of  a  porcelain  front  is  required,  teeth  of  English  manufacture 
may  he  used,  as  the  texture  of  the  porcelain  more  easily  permits 
a  polish  being  giver  to  a  ground  surface. 

Fractures,  Causes  of.- — Teeth  are  sometimes  fractured  Fig.  738. 
in  soldering,  from  the  contraction  of  the  backing  when 
adapted  over  the  edges  of  the  porcelain  in  a  curve  instead 
of  at  a  right  or  slightly  obtuse  angle,  or  from  melting 
solder  on  some  part  of  the  porcelain  which  is  unprotected 
by  a  backing  of  metal.  The  solder,  or  the  borax,  as  it 
cools,  contracting  on  the  porcelain,  or  a  very  thin  edge 
of  the  metal  covering  it,  will  usually  cause  a  fracture. 
The  porcelain  tooth  has  yet  to  be  made  that  will,  as  a 
rule,  endure  such  extreme  treatment  without  breaking. 

Fractures  are  also  caused  by  too  rapid  heating,  and 
quite  frequently  through  impatience  on  the  part  of  the 
operator  by  removal  of  the  work  from  the  investment  before  it 
has  become  perfectly  cool. 

Veneers. — A  veneer  consists  of  a  thin  piece  of  porcelain  repre- 
senting the  labial  aspect  of  the  natural  tooth. 

417 


418  CROWN-,  BRIDGE-,  AXD  PORCELAIN-WORK. 

To  form  a  veneer  select  a  porcelain  tooth  of  the  required  shade 
and  size.  On  the  end  of  a  piece  of  wood,  about  the  size  of  the 
tooth,  melt  and  attach  a  mass  of  shellac,  heat  the  porcelain  tooth 
and  imbed  the  labial  surface  into  the  shellac,  as  shown  in  Fig.  738. 
Clip  off  the  pins  and  with  a  corundum-wheel  on  the  lathe  uni- 
formly grind  down  the  porcelain  until  the  ends  of  the  pins  are 
removed.  Heat  the  porcelain,  release  the  veneer,  and  remove  all 
particles  of  shellac  before  application  of  veneer  to  case. 


CHAPTER    III. 

Pro<  esses.  Methods,  and  Materials. 

impression  trays  —  articulators  —  impressions  -  sectional  im- 
pressions—impression-compound  and  wax— dental  lac— 
models— articulating  impression  or  "bite"  and  model- 
metallic  models  or  dies — fusible  alloys — moldine — how  to 
quickly  make  a  tube  and  fusible  metal  die— counter-die— 
combination  plaster  and  metal  model— cuttlefish  as  a 
molding  material— dental  lac  intaglio  dies-wax  cement. 

Impression  Trays. — In  crown  or  bridge  operations,  as  an  im- 
pression of  only  a  portion  of  the  teeth  is  generally  required,  par- 
tial impression  trays  are  mostly  used.      Trays  suitable  for  the  right 

Fig.  739. 


and  left  sides  and  front  of  the  mouth  are  illustrated  in  Figs.  739 
and  740.  They  are  of  forms  which  favor  the  replacement  of  a 
plaster  impression  in  the  tray  should  it  break  or  be  disturbed  in 
removal  from  the  mouth.  Fig.  741  is  an  adjustable  partial  im- 
pression tray.     This  device  conveniently  takes  the  place  of  three 

419 


420 


CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 


trays.  The  tray  proper  rotates  on  a  pivot  B,  and  is  thus  per- 
fectly adapted  for  use  in  the  front  or  in  either  side  of  the  mouth ; 
and  is  firmly  held  in  position  by  the  sliding  guard  A. 


Articulators. — The  ordinary  form  of  articulator  is  used  in  large 
bridge  operations,  but  for  small  bridges  or  single  crowns,  the 


Fig.  741. 


"partial"  articulator  with  a  graduating  support,  such  as  is  illus- 
trated in  Fig.  742,  is  most  convenient. 

Impressions. — For  the  taking  of  impressions  for  bridge-work 


PROCESSES,  METHODS,  AND  MATERIALS. 


421 


and  most  operations  in  crown-work,  plaster  is  most  suitable.  To 
simplify  the  separation  of  the  impression  from  the  model,  the 
former  being  harder,  as  a  rule,  a  particle  of  carmine  or  other 
coloring  material   may  be   added  to  the   plaster   in   the  mixing. 


Fig.  743. 


Potassium  sulfate  should  be  added  to  quicken  the  setting.  The 
best  method  for  the  purpose  is  to  dissolve  a  small  teaspoon!" ul  of  the 
potassium  sulfate  in  a  pint  bottle  of  water,  and  in  this  way  always 
have  it  ready  for  use  in  the  proper  proportion. 

Sectional  Impressions — AY  hen  the  exact  form  of  the  contour 
of  a  tooth  is  required  or  when  teeth  tip  toward  each  other  in  such 
manner  that  in  the  taking  of  an  impression  the  mass  of  plaster 
which  sets  around  or  between  them  will  not  pull  out,  the  best 
plan  is  to  take  the  impression  in  sections 
(Fig.  743).  Take  palatal  or  lingual  and 
part  of  the  incisal  or  occlusal  surfaces  first, 
remove  that  section,  trim  and  notch,  oil,  A 
replace  in  position  in  the  mouth,  and  ap-  I 
ply  plaster  to  form  the  remaining  section,  a 
Separate  the  sections  for  removal,  replace,  m 
and  run  the  model.  \ 

An  impression  of  this  character  may  also     ^ 
be  obtained  by  taking  the  palatal  or  lingual 
side   first   with   impression-compound,   and  \ 

then  the  labial  with  plaster,  so  that  it  shall  \ 

include  the  entire  occlusal  and  incisal  parts.     This  method  will 


422  OROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

sometimes  simplify  the  taking  of  a  difficult  impression  for  bridge- 
work. 

Another  method  is  to  fit  a  piece  of  softened  impression-com- 
pound accurately  in  position  between  the  overhanging  teeth,  so 
shaped  that  it  will  pull  out  of  the  plaster  impression  on  removal. 
The  piece  of  compound  is  then  removed  from  its  position  in  the 
mouth  and  replaced  in  the  impression  to  complete  the  mold. 
When  the  line  of  an  inter-approximal  space  between  certain  teeth 
is  required,  it  is  best  obtained  by  inserting  between  the  teeth  a 
strip  of  copper,  in  a  single  sheet,  or  doubled,  which  fits  the  space 
closely,  leaving  the  ends  protruding,  before  inserting  the  plaster, 
and  then  removing  the  copper  in  the  impression. 

For  this  class  of  work  surfaces  of  all  kinds  of  which  impressions 
are  to  be  run  with  plaster  require  to  be  thoroughly  varnished  and 
oiled. 

Impression=Compound  and  Wax  are  for  taking  impressions 
of  teeth  for  crowning  purposes,  especially  by  the  seamless  method. 
When  with  either  material  an  impression  of  a  small  space  be- 
tween teeth  is  desired,  it  is  best  obtained  by  first  placing  and 
pressing  a  small,  thin  piece  of  the  material  used  in  the  space  or 
spaces  to  be  taken  before  pressing  the  main  mass  in  the  impres- 
sion-cup to  position  in  the  mouth. 

Dental  Lac  is  a  preparation  resembling  sealing-wax.  It  is  very 
hard  and  tough  for  a  material  of  its  kind,  and  softens  and  hardens 
very  quickly  under  the  application  of  heat  and  cold.  It  is  softened 
for  use  by  holding  it  in  the  heat  above  an  alcohol  or  Bunsen 
flame. 

Dental  Lac  is  useful  for  taking  impressions  and  various  other 
purposes  connected  with  crown-  and  bridge-work  operations. 

Models  on  which  bridge-work  is  constructed  or  soldered  require 
to  lie  made  of  a  material  as  non-shrinkable  when  heated  as  is  prac- 
ticable. Plaster  and  finely  ground  calcined  marble-dust,  mixed  in 
the  proportion  of  1  part  of  marble-dust  to  3  parts  of  plaster  for 
large  models,  and  1  part  of  marble-dust  to  4  parts  of  plaster  for 
small  models,  meets  this  requirement  better  than  any  other  material. 
Either  slips  of  willow  wood  or  brass  pins  may  be  placed  in  the 
impressions  of  such  teeth  as  are  liable  to  be  broken  in  the  removal 
of  the  impression.  Should  fracture  in  removal  occur,  a  thin  mix- 
ture of  oxyphosphate  is  most  suitable  to  repair  the  parts,  as  it 
leaves  them  stronger  than  before. 


PROCESSES,  METHODS,  AXD  MATERIALS.  423 

A  hard  surface  is  given  to  a  model  for  bridge-work  by  first 
running  in  the  impression  a  film  of  a  thin  mixture  of  pure  plaster 
and  then  on  the  surface  of  this  the  mixture  of  plaster  and  marble- 
dust.  This  to  be  effective  has  to  be  dextrously  done.  The  sur- 
face of  models  of  plaster  and  marble-dust  can  be  much  hardened 
by  the  application  of  several  coats  of  very  thin  sandarac  varnish. 

Articulating  Impression  or  "Bite"  and  Model. — This  im- 
pression is  taken  separately  or  at  the  same  time  with  the  impres- 
sion for  the  model.  When  taken  separately  it  has  to  be  done 
with  all  the  crowns  or  caps  in  position  in  the  mouth  previous  to 
the  impression  for  the  model.  Wax  is  generally  used  for  the  pur- 
pose in  preference  to  impression-compound.  Softened  wax,  suffi- 
cient in  quantity  to  barely  cover  the  parts,  is  pressed  over  the  teeth 
and  crowns  to  their  form  and  the  antagonizing  teeth  occluded. 
The  finger  or  cheek  is  pressed  against  the  outside  of  the  wax  and 
the  patient  is  requested  to  press  the  tongue  against  it  on  the  inside. 
The  mouth  is  next  opened,  the  wax  chilled  with  cold  water,  and 
removed.  It  is  generally  best  to  trim  the  impression  of  over- 
hanging superfluous  parts  and  reinsert  it  a  second  time  for  ac- 
curacy. Pieces  of  pattern  tin  placed  over  the  teeth  which  antago- 
nize before  inserting  the  wax  will  prevent  their  biting  through 
the  impression.  The  articulating  impression  is  to  be  placed  in 
position  on  the  model  with  the  caps  or  crowns,  and  the  articulating 
model  run. 

When  impressions  for  both  model  and  ''bite"  are  taken  to- 
gether, the  plaster,  mixed  moderately  thick,  is  with  the  aid  of  a 
spoon,  or  rolled  in  a  mass  with  the  fingers,  which  should  be  im- 
mersed previously  in  water  to  permit  adhesion  of  the  plaster, 
placed  around  in  the  mouth  on  the  crowns,  caps  and  parts  to  be 
included  in  the  bridge,  and  the  antagonizing  teeth  occluded  tightly 
and  so  held  until  the  plaster  sets.  The  mouth  is  then  opened  and 
the  plaster  carefully  removed.  If  the  plaster  breaks  in  removal, 
which  is  usually  the  case,  all  the  pieces  should  be  preserved  and 
carefully  readjusted  in  place.  The  crowns  or  caps  are  generally 
removed  in  the  impression.  If  not,  they  should  be  transferred 
from  the  mouth  to  it.  The  plaster  is  then  varnished  and  oiled, 
and  on  the  side  containing  the  crowns  a  model  of  plaster  and 
marble-dust  in  the  proportion  already  mentioned  is  run.  When 
the  model  has  set,  it  is  mounted  with  plaster  on  an  articulator  and 
an  articulating  model  run  of  pure  plaster,  and  the  opposite  section 


424  GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

of  the  articulator  adjusted.     The  impression  material  is  next  re- 
moved.     (For  further  details  see  page  188.) 

Metallic  Models  or  Dies — Metallic  models  or  dies  of  fusible 
metal  can  be  easily  and  quickly  formed  for  use  in  crown-  and 
bridge-work.      The  melted  alloy  can  be  poured  into   a  plaster, 
moldine,  or  gutta-percha  impression  taken  in  a  tube  or  impression- 
tray.     A  piece  of  copper  plate  or  of  an  old  sepa- 
Fig.  744.         rating  file,  placed  between  teeth  as  shown  in  Fig. 
744,   and  removed  in  position  in  the  impression, 
will  accurately  outline  the  space  between  the  teeth 
in  the  metallic  model.     When  a  tube  is  used,  a 
strip    of    paper    should    be    wound    around    it    to 
lengthen  the  die. 

Fusible   Alloys. — The  following  fusible  alloys 
of  tin  are  suitable  for  the  purpose  : 


Tin. 

Proportions  of 
Lead. 

M 

ETALS. 

Bi 

smu 

th. 

Melting-Point 

of  the  Alloy. 

Fahr. 

1 

2 

2 

236° 

5 

3 

3 

202° 

3 

5 

8 

197° 

Dr.  G.  Molyneaux's  formula  in  parts  is : 

Bismuth,      5  parts. 
Lead,  3     " 

Tin,  2     " 

Cadmium,    2     " 
Melts  at  about  180°. 

Dr.  G.  W.  Melotte,  of  Ithaca,  N.  Y.,  to  whom  is  accorded  the 
credit  of  introducing  the  use  of  fusible  metal  and  the  compound 
called  "Moldine"  into  crown-  and  bridge-work,  gives  the  propor- 
tions of  his  alloy  in  parts  as- — 

Tin,  5  parts. 

Lead,  3     " 

Bismuth,     8     " 

Fusible  metal  should  not  be  heated  much  beyond  the  melting- 
point,  a  matter  which  is  not  as  a  rule  carefully  observed.  It 
should  be  allowed  to  cool  moderately  before  pouring.     In  filling 


PROCESSES,  METHODS,  AXD  MATERIALS. 


425 


some  forms  of  molds  imperfections  in  the  die  are  avoided  by 
pouring  the  metal  just  before  its  congealment.  A  ladle,  such  as 
is  illustrated  in  Fig.  745,  with  legs  to  prevent  tipping  while  cool- 


ing, is  a  suitable  form. 


Dr.  Melotte's  Moldine,  a  preparation  compounded  of  potter's 
clay  and  glycerin  (to  which,  when  needed  to  soften  it,  more  glyc- 
erin can  be  added),  is  very  useful  in  molding. 


Fig.  745. 


Fig.  746. 


How  to  Quickly  Make  a  Tube  and  Fusible=Metal  Die Take 

a  thin  strip  of  copper  plate,  at  least  Xo.  35  gage,  anneal,  and  bend 
it  around  the  tooth  in  the  mouth  or  its  form  on  the  plaster  model. 
Both  ends  of  the  copper  at  the  part  lapped  are  next  cut,  as  shown 
at  A,  Fig.  74-6,  and  turned  over  tight  and  close  in  the  manner 
seen  at  B.  This  fastens  both  ends  of  the  copper,  which,  when 
trimmed  off  at  C,  forms  a  tube.  In  this  tube  take  an  impression 
of  the  natural  crown,  either  in  the  mouth  with  a  little  plaster  or 
moldine  or  from  the  plaster  model  with  moldine  by  trimming 
around  the  tooth  or  by  separating  it  from  the  rest  of  the 
model.  Encircle  the  tube  with  a  strip  of  paper.  Hold 
the  paper  and  tube  with  a  clamp.  Melt  and  pour  the 
fusible  metal  moderately  cool,  and  immerse  tube  and 
metal  in  water.  This  gives  a  die  with  a  long,  narrow 
shank,  which  may  require  to  be  trimmed  at  the  neck 
with  a  file.  When  impression-compound  or  gutta- 
percha is  used,  cool  and  then  dry  the  surface  with  an 
air  syringe  before  pouring  the  fusible  metal. 

Counter=Die — A  counter-die  to  a  small  cast  or  die 
of  fusible  metal  is  made  by  indenting  a  block  of  lead 
with  a  punch,  and  then  driving  the  cast  or  die  into  it. 
Its  use  in  crown-work  is  described  on  pages  103,  112,  and  117. 

A  counter-die  of  fusible  metal  to  a  fusible-metal  die  may  be 
made  by  chilling  the  die  and  oiling  or  vaselining  its  surface  before 
pouring  the  metal. 


426  CROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

Combination    Plaster   and    Metal    Model Dr.   Melotte   has 

introduced  for  special  cases  a  novel  method  of  forming  a  combina- 
tion plaster  and  metal  model,  in  which  the  parts  representing  the 
teeth  are  of  fusible  metal.  The  following  is  a  description :  The 
impression  is  taken  in  plaster.  Iron  pins  to  act  as  dowels  are 
placed  in  the  molds  of  the  teeth.  Pieces  of  a  fusible  metal  which 
melts  at  a  low  point  are  then  melted  into  each  of  the  molds  with 
a  few  puffs  of  the  blowpipe.  Plaster  is  then  poured  in  the  re- 
mainder of  the  impression.  The  advantage  afforded  by  a  model 
of  this  kind,  when  gold  attachments  or  clasps  are  to  be  shaped  to 
teeth,  is  obvious.  The  method  applied  in  the  construction  of 
bridge-work  is  given  on  page  190.  Dr.  Melotte's  formula  for  the 
fusible  metal  used  in  the  above  method  is: 

Bismuth,    8  parts. 
Lead,  4      " 

Zinc,  3      " 

Cadmium,  2      " 
Melts  at  about  150°  F. 

Cuttlefish  as  a  Molding  Material — This  material  affords 
means  of  quickly  and  easily  making  dies  of  grinding-surfaces  of 
teeth  with  zinc  or  Babbitt's  metal  as  well  as  fusible  metal.  Press 
the  model  of  the  grinding-surface  into  the  flat  surface  of  the 
cuttlefish  to  the  desired  depth,  withdraw  model,  and  place  a  me- 
tallic ring  pressed  into  the  surface  of  the  cuttlefish  around  the 
impression.    Next  pour  in  the  metal  to  form  the  die. 

Dental  Lac  Intaglio  Dies. — Dental  Lac  can  be  used  to  make 
intaglio  dies.  Soften  the  Lac  and  press  it  against  the  form  you 
wish  to  duplicate  and  chill  with  cold  water. 

To  stamp  a  piece  of  gold  plate  with  an  intaglio  die  of  Dental 
Lac  place  the  gold  over  the  die.  First  start  the  gold  to  the  form 
by  pressure  from  a  pellet  of  cotton,  then  place  the  die  and  plate 
in  a  swager  with  a  rubber  plunger,  and  bring  down  the  plunger. 
The  Lac  die  will  be  found  to  maintain  its  form  and  perfectly  shape 
the  gold. 

Wax  Cement. — Wax  cement  is  used  in  two  forms,- — adhesive 
and  hard  wax.  Adhesive  wax  when  moderately  heated  is  quite 
flexible,  adheres  readily  to  metal  and  porcelain,  and  may  be  manip- 
ulated with  the  fingers  without  sticking  to  them,  then,  when 
chilled  with  cold  water,  it  becomes  quite  hard.     It  is  to  be  used 


I'h'oCESSES,  METHODS,  A\D  MATERIALS.  427 

during  the  adaptation  of  different  parts  of  the  work  in  and  out  of 
the  mouth. 

Adhesive  wax  of  a  suitable  quality  can  be  made  of  pure  yellow 
beeswax  4  parts,  resin  1  part,  and  gum  dammar  1  part,  by  weight. 

Hard  wax  requires  more  heat  to  soften  it  than  the  adhesive. 

When  sufficiently  heated  it  is  very  soft  and  adhesive,  but  ex- 
ceedingly brittle  when  cooled. 

Hard  wax  is  best  used  as  a  support  to  adhesive  wax.  The  adhe- 
sive wax  having  been  first  applied  in  the  preliminary  adaptation  of 
the  work,  as  much  as  possible  is  removed  without  disturbing  the 
position  of  the  parts  and  replaced  with  the  hard  wax  for  the  final 
adjustment. 

Hard  wax  is  made  of  yellow  beeswax  1  part  and  resin  3  part-. 

Wax  cement  in  the  form  of  stick-  is  the  most  convenient  f<>v 
use. 


2U 


CHAPTER    IV. 

Materials  Principally  Used  for  Investments. 

small  investments — large  investments— method  of  investing — 
preparation  of  investment— heating  the  investment— 
soldering-blocks — blowpipe  and  method  of  using  it- 
preparation,  application,  and  fusing  of  solder — solder- 
pointer— open-flame  soldering — union  by  sweating — sol- 
dering with  a  compound  blowpipe  flame — annealing. 

Materials  Principally  Used  for  Investments. — Calcined  mar- 
ble-dust, both  finely  pulverized,  and  coarse,  common  white  sand, 
and  asbestos,  combined  in  proper  proportions  with  plaster,  are 
principally  used  to  form  investing  material  for  crown-  and  bridge- 
work. 

Small  Investments. — For  small  investments  such  as  single 
crowns,  the  proportions  generally  used  are  2  parts  of  finely  pul- 
verized calcined  marble-dust  to  1  part  plaster. 

Large  Investments. — For  large  investments,  including  pieces 
of  bridge-work,  1  part  finely  pulverized  calcined  marble-dust,  1 
part  sand  or  coarse  marble-dust,  and  1  part  plaster. 

When  used  in  the  proportions  just  described,  the  sand  or  coarse 
marble-dust  prevents  the  excessive  contraction  which  takes  place 
in  large  masses  of  investing  material  entirely  composed  of  fine 
marble-dust,  when  subjected  to  great  heat  for  considerable  time. 
The  fine  marble-dust  in  combination  with  the  plaster  is  more 
suitable  to  fill  in  interstices  and  the  inside  of  caps. 

Asbestos  may  be  substituted  for  sand  or  coarse  marble-dust  in 
large  investments,  as  the  fibre  helps  to  hold  the  material  together, 
but  trimming  has  to  be  carefully  done,  as  the  asbestos  is  not  easily 
cut  and  displacement  of  the  investing  material  and  exposure  of 
some  part  of  the  work  is  liable  to  occur. 

Method  of  Investing.- — In  cases  of  bridge-work,  especially  if 
of  any  great  size,  a  loop  of  iron  wire  should  encircle  the  piece  in 
the   investment. 
428 


MATERIALS  PRINCIPALLY  USED  FOR  INVESTMENTS.        429 

Potassium  sulfate  may  be  used  to  cause  the  mixture  to  set 
quickly  and  hard. 

The  model  on  which  the  bridge-work  is  being  constructed  should 
be  trimmed  as  small  as  is  safe  without  risk  of  fracture.  It  should 
then  be  soaked  in  water  while  the  investing  material  is  being 
thoroughly  mixed. 

The  reduction  of  the  model  is  for  the  purpose  of  securing  the 
presence  of  the  largest  possible  proportion  of  investment  material 
in  the  investment  to  that  of  the  model,  and  its  immersion  in  water 
is  to  prevent  absorption  of  water  from  the  investment  material 
and  to  obtain  a  better  adhesion. 

Preparation  of  the  Investment  for  Soldering. — AY  hen  it  is 
desirable  to  remove  the  wax  connecting  sections  of  a  crown  or 
bridge  in  an  investment  before  heating,  it  should  be  done  by  pour- 
ing boiling  water  on  the  parts.  The  removal  of  wax  with  an 
instrument  is  not  advisable,  as  parts  delicately  held  in  position  are 
liable  to  become  displaced.  The  removal  of  the  wax  exposes  the 
metallic  portions  of  the  work  to  be  soldered.  All  surplus  and 
especially  overhanging  investment  material  should  be  removed, 
but  parts  already  soldered  should  be  left  covered. 

The  metallic  parts  to  be  soldered  should  be  exposed  as  much  as 
possible  so  as  to  be  accessible  to  the  direct  flame  of  the  blowpipe, 
as  the  greater  their  depression  in  the  investment  material,  the 
more  difficulty  will  be  experienced  in  guiding  and  controlling  the 
solder  at  that  point  with  the  blowpipe. 

Care  should  be  taken  that  all  parts  of  the  porcelain  teeth  are 
covered  and  all  crevices  between  them  filled  with  the  investment 
material  to  prevent  invasion  of  borax  or  solder,  either  of  which 
is  very  liable  to  cause  their  fracture.  The  filling  in  with  gold  foil 
of  small  open  seams  between  sections  of  metal  facilitates  their 
union  in  soldering.  The  filling  in  of  large  spaces  under  caps  or 
tips  to  porcelain  fronts  can  also  be  much  assisted  by  packing  in  the 
spaces  large  pellets  of  foil  or  by  placing  in  them  pieces  of  plate  or 
wire.  A  moderate  application  of  flux  may  now  be  made  to  the 
deeply  invested  parts,  as  directed  under  article  on  "Flux,"  page  41 6. 

Many  prefer  to  trim  the  investment  and  let  the  wax  burn  out  as 
the  investment  is  heated.  This  is  done  when  fluxed  wax  is  used 
and  the  benefit  of  the  flux  is  to  be  obtained.  The  objection  to  the 
burning  out  of  wax  is  that  owing  to  the  resultant  debris  pits  are 
more  liable  to  be  found  afterward  in  the  solder. 


430 


CROWN-,  BRIDGE-.  AXD  PORCELAIX-WORK. 


Heating  the  Investment — In  soldering  crowns  and  bridge- 
work  or  sections  of  it  containing  porcelain  fronts,  the  investment 
should  be  first  uniformly,  gradually,  and  thoroughly  heated  over 
a  Bunsen  flame  until  the  bottom  of  the  investment  assumes  a  dull 
red  shade. 

A  piece  of  heavy  iron  wire,  about  No.  8  gage,  bent  in  the  form 
of  a  scroll,  as  shown  in  Fig.  747,  or  a  piece  of  sheet  iron  per- 
forated with  large  holes  placed  across  the  top  of  a  spider  fitted  to 
the  burner,  forms  a  good  support.  When  heated,  the  investment 
should  be  removed  to  a  soldering-block. 

Soldering=Blocks. — A  large  round  piece  of  charcoal,  about 
5  inches  in  diameter  and  6  inches  long,  cut  or  burned  out  a  little 
concave  on  one  end,  and  with  a  thin  covering  of  plaster  to  prevent 
soiling  the  hands,  furnishes  a  good  soldering  support  and  one  that 
will  retain  the  heat.  It  is  the  form  preferred  by  the  author. 
Seams  or  cracks  in  the  charcoal  should  be  filled  in  with  a  mixture 
of  sand  or  asbestos  and  plaster,  to  retard  the  burning  out  of  the 
block.  Two  or  three  iron  nails  inserted  in  the  concavity  of  the 
block,  a  little  to  one  side  of  the  centre,  are  useful  at  times  to  prop 
up  an  investment.  Manufactured  soldering-blocks,  such  as  those 
shown  in  Fig.  748,  are  used  preferably  to  charcoal  by  many. 


Fig.  747. 


Fig.  748. 


W 


Blowpipe  and   Method  of  Using  It. — A  hand  gas  blowpipe 

(Fig.  749)  operated  by  a  foot-bellows  of  medium  size  and  so  con- 
structed as  to  be  under  perfect  control,  especially  respecting 
diminution  of  the  flame  to  a  very  small  point,  makes  the  most 
satisfactory  apparatus. 


MATERIALS  PRINCIPALLY  USED  FOR  INVESTMENTS. 


431 


The  full  flame  of  the  blowpipe  should  be 
directed  at  first  under  and  around  the  sides 
of  an  investment,  which  should  be  slightly 
tipped  or  propped  up  at  one  side  for  the  pur- 
pose. The  investment  should  in  this  man- 
ner at  tirst  be  uniformly  heated  to  a  point 
sufficient  to  melt  the  solder  without  pointing 
the  dame.  AVhen  the  heat  of  the  surface  of 
a  piece  of  metal  is  lower  than  that  required 
to  fuse  the  applied  solder,  the  solder  is  liable 
t<>  ball  up  and  roll  off.  The  tendency  of 
melted  solder  is  to  flow  to  the  hottest  point. 
It  is  also  affected  by  gravitation.  By  the 
application  with  the  blowpipe  of  a  greater 
degree  of  heat  under  an  investmenl  than 
on  the  top  the  solder  can  be  drawn  down  into 
the  deeply  invested  parrs.  But  if  after  flow- 
ing solder  to  and  in  these  parts  a  heat  is 
still  maintained  more  than  sufficient  to  keep 
the  solder  in  a  molten  condition,  and  a 
slightly  greater  heat  i-  applied  to  the  surface 
section  of  the  investment,  the  -older  is  liable 
to  he  drawn  upward.  In  this  manner,  in  the 
soldering  of  a  collar  crown  the  solder  thai 
has  been  drawn  down  between  the  porcelain 
front  and  cap  and  around  the  collar  on  a  line 
with  the  porcelain  is  liable  to  be  largely 
drawn  backward  and  absorbed  in  the  final 
soldering  of  the  backing  and  contouring  of 
the  crown;  therefore  in  soldering  the  work, 
especially  crowns  and  dummies  with  porce- 
lain fronts,  these  points  should  be  borne  in 
mind.  AVhen  certain  parts  of  the  work  have 
been  united  and  generally  filled  in  with  the 
solder  under  the  effect  of  the  large  flame,  the 
flame  may  then  be  reduced  in  volume  and 
pointed  for  a  moment  to  guide  the  solder  to 
and  better  shape  it  at  some  special  point. 
Proper  position  for  the  investment  and  cor- 
rect application  of  the  heat  in  soldering  aid 
in  accomplishing  the  desired  result. 


Fig.  749. 


432 


CROVX-,  BRIDGE-,  AXD  P0RCELAIX-1Y0RK. 


Fig. 


W 


Preparation,  Application,  and  Fusing  of  the 
Solder. — The  solder  should  be  cut  in  small  square 
and  oblong  pieces  and  placed  on  the  cover  of  a  tin 
box  within  convenient  reach  of  the  points  of  the 
tweezers.  The  pieces  may  be  coated  with  borax 
finely  ground  in  water,  but  they  should  be  allowed 
to  dry  before  application.  The  solder  should  not  be 
applied  until  the  investment  has  been  first  brought 
to  a  red  heat  on  the  soldering-block  with  the  blow- 
pipe, and  then  only  at  the  part  where  the  soldering 
is  commenced.  It  should  be  applied  a  little  at  a 
time.  The  portion  placed  in  the  investment  should 
be  first  melted  and  flowed  down  into  the  inter- 
stices of  the  work,  using  the  large  flame  of  the  blow- 
pipe under  and  around  the  investment.  More  solder 
is  then  added  by  degrees,  and,  finally,  as  the  parts  be- 
come filled,  by  the  use  of  a  smaller  flame  applied 
directly  to  the  part  and  the  judicious  use  at  times  of 
a  small-pointed  flame  and  the  addition  of  solder  the 
parts  can  be  given  the  desired  form. 

A  pair  of  soldering-tweezers  with  a  long  reach  and 
small  curved  points,  as  illustrated  in  Fig.  750,  should 
be  used  to  pick  up  and  place  the  small  pieces  of 
solder. 

Solder  =  Pointer — A  small-pointed  instrument 
with  a  long  handle,  termed  a  "solder-pointer,"  is  use- 
ful at  times  to  stir  up,  spread,  and  draw  the  solder 
to  a  desired  point.  The  point  of  the  instrument 
should  preferably  be  made  of  platinum  instead  of 
steel. 

In  large  pieces  of  bridge-work  with  considerable 
curve  it  will  be  found  necessary  to  solder  a  portion 
at  a  time.  This  is  best  done  by  placing  each  portion 
as  it  is  to  be  soldered  in  the  deepest  part  of  the  con- 
cavity of  the  soldering-block,  and  when  soldered, 
slightly  cooling  and  changing  the  position  of  the 
investment,  as  gravity  tends  to  carry  the  melted 
solder  to  the  lowest  point. 

Open=Flame  Soldering. — Open-flame  soldering  is 
done  either  in  a  Bunsen  (gas)  flame  or  the  flame  of 
an  alcohol  lamp.     It  is  the  method  used  for  solder- 


MATERIALS  PRINCIPALLY  USED  FOR  INVESTMENTS. 


433 


ing  small  sections  of  the  work,  as  the  seams  of  collars,  and  caps 
to  collars.  A  Bunsen  burner  of  the  form  illustrated  in  Fig.  751 
(one-half  size)  is  a  most  convenient  one  for  general  use,  as  it  per- 
mits the  supply  of  air  to  the  centre  of  the  flame  to  be  regulated. 

The  metal  is  held  by  a  clamp  and  heated  in  the  flame  as  shown 
in  Fig.  144.  The  heat  should  be  applied  gradually,  and  the  metal 
first  held  above  the  flame  and  then  -lowly  brought  downward  into 
it.  to  a  point  just  above  the  hollow,  and  held  there  as  briefly  or  as 

Fig.  751. 


long  as  is  necessary  to  effect  the  desired  fusion.  For  soldering 
sections  of  the  work  which  cannot  be  clamped  together  the  wire 
frame  illustrated  in  miniature  in  Fig.  752  is  often  serviceable. 
The  parts  to  be  soldered  are  laid  with  the  solder  in  position  on  the 
centre  of  the  wire  network  and  introduced  into  the  flame. 

Dampened  finely  ground  calcined  marble-dust,  applied  in  a  thin 
layer  on  the  inner  surface  of  a  cap  or  collar,  will  prevent  an 
invasion  of  the  solder.  The  marble-dust  is  afterward  easily 
washed  out,  which  is  not  the  case  with  whiting,  often  used  for 
the  purpose. 


434 


CROWN-,  BRIDGE-,  AXD  PORCELAIN -WORK. 


Union  by  Sweating  consists  in  uniting  the  edges  or  surfaces  of 

two  pieces  of  metal  by  heating  them  so  closely  to  the  fusing-point 
that  union  takes  place  without  melting  the  main  body  of  the  metal. 
This  process  is  sometimes  used  to  unite  the  seam  of  a  collar.  The 
clean  edges  of  the  metal  are  brought  together  or  lapped,  flux  is 
placed  in  the  seam,  and  the  heat  carefully  raised  to  the  fusing- 
point.  This  is  slightly  facilitated  by  the  flux,  which  by  prevent- 
ing oxidation  causes  the  surfaces  to  fuse  and  unite  before  the  main 
body  of  the  metal  melts. 

Soldering  with  a  Compound  Blowpipe  Flame. — Platinum 
solder  requires  a  compound  blowpipe  flame  to  melt  it.  This  can 
lie  improvised  by  connecting  the  air  tube  of  an  ordinary  gas  blow- 
pipe to  that  of  a  cylinder  of  nitrous  oxid  gas.  The  flame  of  the 
blowpipe  should  be  reduced  to  a  very  small  jet  and  the  volume 
of  the  nitrons  oxid   turned  on  very  slowly   until   an   amount  of 

Fig.  752. 


l\ 

m 

■ 

■*■*■' 

f -.14- 

-=^Ei 

---i 

:  1 1 1 11  Mi 

pressure  is  reached  sufficient  to  poinl  the  flame  and  effect  perfect 
combustion. 

A  small  compound  blowpipe  invented  by  Dr.  Rollo  Knapp  is 
specially  made  for  this  purpose,  and  is  described  below,  but  the 
fusing  of  platinum  snider  can  be  effected  quite  satisfactorily  with 
the  ordinary  blowpipe  above  described. 

Dr.  Knapp's  Compound  Blowpipe  (Fig.  753)  consists  of  a 
miniature  blowpipe  in  which  the  ordinary  illuminating  gas  (car- 
buretted  hydrogen  or  coal  gas)  flame  is  combined  with  a  current 
of  nitrous  oxid  from  a  cylinder  of  the  condensed  gas.  The  com- 
biiiiition  of  these  gases  in  combustion  forms  essentially  a  carbo- 
oxyhydrogen  flame1     By  means  of  a  yoke  and  set-screw,  the  valve 

1  The  ordinary  compound  oxyhydrogen  blowpipe  flame  is  proauced  by 
2  volumes  of  hydrogen;  1  volume  of  oxygen. 

Carburetted  hydrogen  consists  of 

2  volumes  of  hydrogen;  1  volume  of  carbon. 

And   nit  rous  oxid  of 

2  volumes  of  nitrogen;   1  volume  of  oxygen. 

Consequently  Knapp's  blowpipe  flame  is  produced  by  a  mechanical  mixture  of 
2  volumes  of  hydrogen;  1  volume  of  oxygen;  1  volume  of  carbon. 


MATERIALS  PRINCIPALLY  I  8ED  FOR  /Vl  ESTMENTS.        43:5 

of  the  cylinder  is  connected  with  the  tubes  and  valves  of  the  blow- 
pipe, so  that  the  proportions  of  the  mixture  of  nitrous  oxid  and  the 
illuminating  gases  are  under  perfect  control.  The  flame-jet  can 
l»e  diminished  to  half  an  inch  in  length,  and  at  that  size  will  melt 
a  small  piece  of  gold  plate. 

I'n..  753. 


Where  illuminating  gas  is  not  available,  an  apparatus  termed 
a  carburetter  can  be  used,  which  supplies  the  deficiency  in  a 
simple  manner  by  vaporizing  naphtha. 

This  blowpipe  is  useful  for  many  purposes  in  the  laboratory 


436  GROWN-,  BRIDGE-,  AND  PORCELAIN-WORK. 

of  the  present  time,  especially  in  forming  solid  gold  backings  to 
dummies  for  bridge-work,  strengthening  seamless  gold  crowns,  and 
forming  solid  gold  crowns. 

Annealing. — Annealing  gold  is  done  either  with  the  open  flame 
or  the  blowpipe,  or  in  the  muffle  of  a  furnace ;  in  the  open  flame, 
by  holding  the  piece  of  plate  with  a  clamp  in  the  upper  part  of  the 
flame,  until  as  high  a  degree  of  heat  is  reached  as  the  character 
or  carat  of  the  plate  will  permit  without  melting.  Pure  gold 
will  permit  a  light  yellow  heat;  18  to  22-carat  plate,  from  a  dull 
to  a  bright  red.  Large  pieces  of  gold  require  to  be  laid  on  a  solder- 
ing-block  and  heated  with  a  blowpipe. 

Platinum  is  best  annealed  in  an  alcohol  flame  or  in  the  muffle 
of  a  furnace.  It  requires  to  be  brought  to  a  white  heat  and  kept 
there  for  a  short  time.  In  a  gas  flame  platinum  suffers  deteriora- 
tion by  the  formation  of  carbide  of  platinum,  which  in  oxidizing 
later  is  liable  to  blister  the  metal. 

The  best  results  in  annealing  arc  accomplished  by  allowing  the 
metal  to  cool  slowly.  Much  time,  though,  is  often  gained  by  im- 
mersing in  water.  This,  however,  should  not  be  practiced  with  in- 
gots of  gold  or  silver  just  melted. 

Each  time  metal  is  bent,  burnished,  hammered,  drawn,  or 
rolled,  its  softness,  flexibility,  and  ductility  are  impaired,  but  they 
are  instantly  restored  by  annealing.  This  fact  should  be  borne  in 
mind  in  the  manipulation  of  metal  in  the  construction  of  all  forms 
of  work. 


I    II  A  I'T  EK    V. 
Instruments,  Appliances,  And  Material  Specially  Required. 

The  dentisl  who  intends  to  i  extensively  in  crown-  and 

bridge-work,  and  who  desire-  to  practice  it  conveniently  and  suc- 
cessfully, should  supply  himself  with  all  the  accessary  instru- 
ments, tools,  and  other  appliances.     These  consist  principally  of: 

Suitable  drills  and  burs,  including-  three  or  four  sizes  of  the 
Gates-Glidden  for  root-canals;  root-trimming  and  shaping  instru- 
ments, gem  and  corundum-wheels  and  points,  and  vulcarbo  disks. 
(See  pages  34  and  35.) 

Pliers  for  shaping  collars  (see  page  75),  and  a  pair  of  excising 
forceps. 

Soldering-clamps  (see  page  104)  and  hand-vise. 

Small-pointed  shears. 

Round  and  half-round  plate  files,  very  finely  cur. 

A  small  anvil. 

Bunsen  gas-burner  and  spider  attachment  for  heating  invest- 
ments for  soldering. 

A  gas  blowpipe  with  bellows,  and  a  mouth  blowpipe. 

Charcoal  soldering  block. 

Calcined  marble-dust. 

Potassium  sulfate. 

Melotte's  Moldine  and  fusible  metal. 

The  prepared  wax  cement,  as  described  at  page  426,  or  Parr's 
fluxed  wax. 

Dies  and  plates  for  forming  gold  caps  for  use  in  constructing 
crowns  and  capping  dummies. 

Copper  plate  Xos.  34  to  35  gage,  copper  wire  Xo.  30  gage, 
fine  iron  binding-wire,  and  heavy  iron  wire  to  encircle  invest- 
ments. 

Pure  gold  plates  Xos.  28  to  30  gage,  22-carat  gold  plate  Xos. 
28  and  30  gage,  and  18-  and  20-carat  gold  solder. 

Platinum  plate  Xos.  30  and  32  gage  for  collars,  heavy  and 
very  light  platinum  plate  and  foil  for  backings,  platinum  and 

437 


438  CROWN-,  BRIDGE-,  AND  PORCELAIN  WORK. 

iridiq-platinum  wire  Nos.  15  and  17  gage  for  posts,  and  fine  plati- 
num wire,  about  Xo.  19  or  20  gage,  for  pins  in  either  gold  tips 
or  crowns. 

A  small  assortment  of  cross-pin  plate  teeth  of  light,  medium, 
and  dark  shades,  consisting  of  incisors,  cuspids,  and  a  few  bicuspid 
and  molar  fronts  for  dummies. 

A  small  rolling-mill  for  plate  will  be  quite  an  acquisition,  as 
gold  scraps  can  be  remelted  and  formed  into  plate,  and  plate  on 
hand  reduced  to  any  desired  gage. 

For  porcelain-work,  an  outfit  of  preferably  high -fusing  porce- 
lain body,  as  it  can  be  used  for  both  inlay-  and  crown-work. 

Fig.  754. 


Three  camel's-hair  brushes — small,  medium,  and  large. 

A  small  spatula. 

A  small  slab  or  platinum  tray  for  holding  the  work  while 
baking. 

Pulverized  silex. 

One  dwt.  of  platinum  1/1000  gage 

A  set  of  suitable  burnishers  for  adaptation  of  matrices. 

An  electric  furnace,  preferably  with  a  pyrometer,  or  a  gasoline 
furnace  for  the  baking  of  porcelain. 

The  bench  on  which  the  principal  parts  of  the  work  are  done 
should  be  specially  designed  and  reserved  for  it.     Tt  should  bo 


INSTRUMENTS,  APPLIANCES,  AND    MATERIAL. 


439 


in  the  same  room,  and  conveniently  situated  a  little  behind  the 
dental  chair,  out  of  view  of  the  patient.  Everything  connected 
with  this  bench  should  be  kept  in  order  and  ready  for  immediate 
use.  Sneh  a  bench,  made  of  oak  or  black  walnut,  with  a  top  that 
can  be  closed  when  not  in  use,  making  an  unobjectionable  piece  of 
furniture,  is  represented  in  Figs.  7.">4  and  755. 

The  Bunsen  flame  in  the  centre  of   the  bench  can  be  turned  off 

and  relighted  instantly  by  a  small  jet  at  the  side  of  the  burner. 

The  point  of  the  socket  of  the  gas  brackel  i-  formed  so  that  when 

the  bracket  is  pushed  to  one  side  for  the  purpose  of  closing  the 

cover  of  the  bench  the  gas  supply  i-  -hut  off.     Although  soldering 

I'n,.  755. 


with  the  regular  gas  blowpipe  may  lie  done  at  this  bench  as  well  as 
that  by  the  open  flame,  the  laboratory  is  a  more  suitable  place  for 
the  former,  as  the  smoke  emanating  from  the  gas  will  soil  the 
adjacent  walls  and  ceiling. 

An  office  lathe  should  be  kept  next  to  the  bench,  or  a  small 
lathe-head  can  be  mounted  on  the  bench  and  operated  by  an 
electric  motor. 


INDEX. 


Ahkasion   of  incisal   edges  of  teeth,  99, 
110. 
method  of  forming  crown  for,  99,  110, 

257,   334. 
method  of  forming  tip  for,  155. 
Abscess,   chronic  alveolar,   treatment  of, 

27. 
Acid,  arsenous,  its  use  and  action  in  de- 
vitalizing pulps,   13. 
Acid  secretions,  platinum   unaffected  by, 

81. 
Adaptation  of  gold  collars,  74. 

to  ready-made  porcelain  crowns,  method 
of,   138. 
Adjuster     for     use     in     cementation     of 

crowns,  1GG. 
Adjustment    of    finished    bridge-work    in 

the  mouth,  197. 
Adjustment   of   seamless    crowns,    122. 
Alexander's  method  of  forming  gold   in- 
lays and  tips,    157. 
All-gold  bridge-work.    204,   206,   316. 
All-gold  collar  crowns,  101,  115. 
constructed  in  sections,  74. 
seamless,  112. 
Alloy    for    forming    any    grade    of    gold 

solder,  414. 
Alloys   of   tin,   their    use   in   crown-work, 

424. 
Alveolar  abscess,   classification   of,   28. 

treatment  of,   27. 
Alveolarotomy,  29. 
Amalgam,   use  of.   in  bridge-work,   225. 

in   crown-work,   37,  40. 
Amputation  of  the  apex  of  a  root,  32. 
Analysis  of  dentin,  7. 
Anatomical    structure   of   dentin,    5. 
Anchorage  bars  in  bridge-work,  188,  194, 
205,    223,   224. 
spur,  223. 

attaching  to  the  abutments,  193. 
Anchorages  or  abutments  for  bridge-work, 
preparation   of,   182,   201,   218,    224, 
229,   234,   249. 
Dr.   Litch's  method,   300. 
Dr.   Winder's  method,   304. 
shell,    209,    245,    247,    250. 


Ancient  bridge-work,  177. 
Anesthesia   in  pulp-extraction,    11. 
Anesthetics,  local,  for  application  to  gum, 
30. 
use  of,  in  crown-work,  80. 
Annealing,  436. 
Antagonizing  teeth,   preparation   of  their 

cusps,  39,  ls7. 
Antiseptic  agents  in  treatment  of  alveo- 
lar abscess,   31. 
in  treatment  of  pulpless  teeth,  21. 
Anvil,  use  of.   in  crown-work,  70. 
Aristol,  use  of,  in  pulp  canal,  22. 
Arsenous  acid,   use   of,   in   devitalization 

of  the  pulp,  13. 
Articulation   for  bridge-work,   manner  of 

taking,   1S9,   323. 
Artificial    crown-work,    history    of,    45. 
the  gold  system.  74. 
the  porcelain  system,  61. 
Artificial  gum   in   porcelain   bridge  work, 
107. 
in  inlay-work,  378. 
Asepsis,    dependence    of    crown-work    on, 

26. 

Ash's  Dental  Lac,  422. 
Ash's  tube-teeth  and  crowns,  70. 
Artificial  teeth,  selection  of.  60,   417. 
Attachments   for  removable   bridge-work, 

135,  271,  295,  298,  304,  309 
Attachments  for   removable   bridge-work, 

the    Griswold,    309. 

Backings  for  porcelain  fronts  in  crown- 

or  bridge-work,  89,  00,  191,  102,  239. 

Baldwin's    method    of    mounting    crowns, 

138. 
Bar  bridge-work.  188,  205,  224,  234,  240, 
251,  328,  404. 
advantages  of,   227,  228. 
anchoring  of  the  bar,  225,  228. 
extension,  181.  227. 
gold  inlay,    228. 
in  bicuspids  and  molars,  228. 
in  incisors  and  cuspids,  224. 
Bars,  connecting,  207,  243.  244,  27S,  294. 
Bars  for  bridges,  193,  225,  234. 

441 


443 


INDEX. 


Beers's   crowns.   47. 
Bing's   bridge-work,    ITS. 
Blind  abscess,  treatment  of,  28. 
Blowpipes,  Lee's,  431. 

carbo-oxyhydrogen,  434. 
Bonwill,   Gates-,  porcelain  crowns,  48. 
Bonwill's    removable    plate-bridges,    208. 
Borax,    method   of   using    in    crown-    and 
bridge-work     in     constructing     root- 
caps   and   tubes,   94,   41G,   432. 
Brewster  crown,  69. 
Bridge-work,   175,   177. 

adjustment  and  attachment,  197. 

advantages  of  detachable,  266. 

as   affecting  hygienic   condition   of   the 

mouth,    268. 
cantilever,  222,  223. 
cases,    illustrating   the   application    of, 

243,   325. 
cementation  of,   162,   167,   198,    212. 
connecting    sections    with    bars,     193, 

225,   234. 
construction   of,    187,    243,   270. 
criticism   of,  impartial,   179,   21 8,   260. 
detachable.    135,    270,    304. 
extension,  218. 

extensive  application  of,  253. 
foundations    for,    181,    218,    224,    243, 

325. 
general  application  of,  243. 
history   of.   177. 
how  to  cement  any  form  so  it  is  easily 

removed,  167,  172. 
manner  of   taking   impression   ami    ar- 
ticulation   for,    188,    198,    2V.>.    24::, 
280,    287,    314,    315. 
mechanical     principles    governing    the 
process    of    construction,    181,    218, 
225. 
partial   cap   and   pin,    229,   232,   236. 
plate,  287,   331. 
porcelain,  403. 
methods   in   pyorrhea,   234. 
removable.   270,  287. 
removal    of.   200,    207. 
selection  of  abutments,  181,  218,  243. 
versus  self-cleansing  spaces,   193,  204. 
Bryant's   method    of    repairing    fractured 
porcelain  fronts,  205. 

Cantilever  bridge-work,   222,   223. 

crown,  146. 
Cap  for  collar,  to  construct,  85,  97,  102, 
310. 

for  porcelain  crown,  137,  391. 
Cajjping   pulps,   meilicids   of,   8. 
Carmicbael   cap,   21.'!. 
Cast   fillings,   153. 

to  support  bridge-work,  228. 


Cataphoresis,   11. 

Cement,    advantages    of   improved    forms 
of,    50. 
gutta-percha,  167. 

oxyphosphate    and    gutta-percha    com- 
bined, 165,  172. 
to    cause    gutta-percha    to    adhere    to 

tooth-structure,  170,  172. 
to  cause  to  set  slowly,  162. 
Cementation    of    crown-    or    bridge-work, 
162,   197,  212. 
to  be  easily  removed,  165,  172. 
Chronic  alveolar  abscess,   27. 
Circulation  in  dentin,   5. 
Clamps,   soldering,    77,   103,   104. 
Cleansing  of  bridge-work  when  worn  by 

patients.  269. 
Cocain,  use  of,  11,  32,  SO. 
Collar,  to  contract,  80. 
Collar  crowns,  74. 

bicuspids  and  molars,  95,  101. 
hygienically    considered,    71,    81. 
incisors  and  cuspids,  83,  135,  137. 
preparation  of  teeth  or  roots  for.  34. 
Collar  expansion,  80. 
Collar  pliers,   75.    101. 
Collars,    method   of   adaptation   of   seam- 
less crowns,   121'. 
to  solder,   76,   77,    12  1. 
Collars    for    crowns,    74.    112,    131,    138, 
316,  391. 
construction  and  adaptation  of.  74,  95, 
131,    135. 
Connecting  liars  in  bridge  work.  207,  234, 

243,    279,    284.   .",29,   331. 
Construction    of    bridge-work,    181,    198, 
201,  224,  229,  234,  243,  270,  403. 
detachable  and  removable,   270. 
mechanical    principles   governing,    181, 

218,    222,    224,    243. 
plate,  286. 

saddles,  218,  255,  287. 
small  pieces  of,  198,  219,  243. 
special    processes    and    appliances    in, 
201. 
Contour,  use  of  a  swager  to   impart,    to 

seamless  gold  crowns,  119. 
Corundum-wheels  and  points,   34,  35. 
criticism    of   crown   and   bridge   opera- 
tions, 179,  218,  260. 
Crown-   and   bridge-work   combined    with 
operative    dentistry    in    dental    pros- 
thesis,   71,    81,    128,    179,    212,    218, 
231,  255,  260,  325. 
instruments  and  appliances,  437. 
Crowns,  history  of  artificial,  45. 
Ash's  tube-teeth  and  crowns,  70. 
Baldwin's  method  of  mounting,  138. 
Bonwlll-Gates,   18. 


INDEX. 


443 


Crowns,   Brewster,  69 
Chupein,  131. 
cup-shaped  cap,  131. 
Davis,  09. 
Evans's  gold,  121. 
Evans's  posl  and  disk  method,   132. 
Fellowship,  69. 
Farrar's  cantilever,   140. 
Fillebrown's,  220. 
poster,    IT 
Uates-Bouwill.    18. 
gold,  74. 

Hollingsworth,  316. 
Bowland-Perry,    18 
Logan,  G4. 
Parr,  135. 
Patrick,  109. 

platinum   and  porcelain,   391. 
Perry-1 1"\\  land,  48. 
ready-made,  61,   121. 
Richmond,  46. 
saddle-back,  97. 

criticism  of  crowns  without  collars,  71 
principles  Involved  in,  .">_. 

Stowell's  thod  of  mounting,  98 

temporary,  72. 

Van  Woert,  131. 

Weston,  4!). 

White's,  Gordon,  method,  137. 

with   vulcanite  attachment,   71'. 

all  gold  in  sections,   74,    101. 

attachments   for  all  gold   and   seamless 

gold,  40,   100,    170. 
cementation,   process  of,  07,    162,   I'll', 
contouring  of  clowns  and  collars,    101, 

118. 
contraction  of,  80,  118,   L24. 
dies    for    use    in    construction    of,    95, 

102,    111,    Hi'.    115,    129. 
expanding,  79,   I  23. 
linishing  and  polishing,   160. 
for  abraded  teeth,  99,  no. 
for  separate  molar  roots,   1  Iti. 
gold  and  porcelain  for  teeth  with   liv- 
ing pulps,  99,  100,  322. 
gold    and    porcelain    without    a    collar, 

137. 
gold  collar,   74. 
gold  seamless  cap,  112. 
gold  seamless  contour,  122. 
nomenclature  of,  52. 
partial,  140,  209. 
porcelain   with   collar   attachment,    83, 

133,  138. 
porcelain    with    vulcanite    attachment, 

72. 
preparation  of  crown  or  root  for,  3,  34. 
process  of  adjustment  of  gold  contour, 

seamless,  122. 

30 


Crowns,  remarks  on  the  use  of  collar  or 
porcelain,  71,  81. 
removal  of,  200. 
repair  <>f.  262. 

Shell,    209,    244.    245,    248,    249 
temporary,  72. 
Cusps  of  antagonizing  teeth,  preparation 
of,  39,  189. 

DAVENPOHT  removable  plate  bridge-work, 

299. 
Mavis  crown,  69. 

method  of  mounting  on  cap  root,  139. 
Decayed  roots,  >i'<ii;i I  preparation  of.  tor 

crown-work,   40. 
i  lental  Lac,  use  of,  tor  molds,   122. 
Dentin,  circulation   in,  5. 

chemical  analysis  of,  7. 
Detachable  bridge-work,  270,  287,  304 

porcelain  front,  239 
Devitalization  of  pulps,   11. 

by  cataphoresls,  1 1. 

instantaneous,  1 1. 

use  of  arsenic   lor,    13. 

use  of  cocain  in,  11,   1.".. 
Diatoric   tooth  dummies,   Sanger,   202. 
Die  plate,  107,  111,  ::17. 
Dies,    '.I.",,    It H,     lo7.    111.    112,    110,    119, 
127,  2li::.  21  1,  424. 

Dr.  Melotte"s  method  for  forming,  424. 

counter-,  1 1 3,  1 1 7.  425. 

fusible-metal,  42  1 
Diseased  pulps,   classification   of,    requir- 
ing extirpation,  8. 
Diseased  teeth  or  roots,  badly,  3. 

with  necrosis  of  alveoli.  .".. 
Disinfection  of  dentin,  8. 

of  root-canals  and  dentin,  18. 
Disks,   forms  of,   35. 
Drills,      Gates-Glidden,      form      of,      and 

method   of   using,    U\. 
Dummies,    definition    of,    191. 

how  to  form,  191,  201. 

how   to   form,   of  solid   gold,   204. 

how  to  form  hollow,  of  gold,  206. 

how    to  form,  in  one  continuous  piece. 
323. 
I  rwinelle's  crown,  74. 

English  bridge-work,  178. 
Kvans's  gold  crowns,  121. 

method  of  inlaying  with  Jenkins  porce- 
lain,  400. 
method   of   constructing  all-gold   dum- 
mies in  bridge-work,  204,  206. 
Krosion,  use  of  porcelain  inlay  in,  378. 
Kxcision  of  natural  crown,  12,  36. 

and    instantaneous    extirpation    of    the 
pulp,  12. 


444 


INDEX. 


Excision    of    natural     crown,     when    to 

avoid,  7,  8. 
Expansion  of  a  collar  or  crown,  80,  123. 
Extension  bar  bridge,  227. 
Extension  bridges,  218. 

leverage  in,   218. 
Extirpation  of  pulps,  11. 

Pacing,  porcelain,  for   metallic   crowns, 
88,  95,  97,  98,  99,  137,  322,  391. 

removable  and  replaceable,  239. 
Farrar's  cantilever  crown,  146. 
Fellowship   crown,   69. 
Files  for  trimming  roots  of  crowns,  35. 
Fillebrown's  crown,  220. 
Filling  of  root-canals,  23. 
Finishing  and  polishing  bridge-work,  161, 
196. 

crown-work,  161. 

flange   to  better  support   a    porcelain- 
faced  gold  crown,  131. 

to  better  support  bridge-work,  222. 
Flux,  94,  416. 
Forceps  for  excising  natural  crowns,  12. 

for  removing  crowns.  2(17 
Formulas  for  fusible  metals,  424. 

for  gold  plates  and  solders,  411. 

for  platinum  solder,  416. 

for  silver  solder,  415. 
Foster  crown,  47. 
Foundations    for    bridge-work,    181,    218, 

224,  229,  234,  243. 
Fracture  of  porcelain  teeth  in  soldering, 

417. 
Fractured  teeth  and  roots,  treatment  of, 
for  crowning,  140. 

Sanger's  method,  141. 
French  bridge-work,  178. 
Fusible  alloys  of  tin,  424. 

Melotte's,  424. 
Furnaces  for  fusing  porcelain,  344. 

Gates-Bonwii.l  crown,  48. 
Gold,  refining  and  melting  of,  413. 
Gold,  all-,    crowns   for   front   teeth,   109, 
117. 

for  bicuspids  and  molars,  101,  112,  316. 

hollow  dummies  for  bridges,  206. 

solid  dummies  for  bridges,  204. 
Gold  caps,  seamless,  how  to  stamp,  113. 
Gold  cap-crown,  to  securely  attach,  171, 

172,  205,  250. 
Gold  collar  crowns,  74,  101,  112,  316. 

with  porcelain  fronts,  83. 

preparing  natural  teetb  for,  5,  34,  186. 
Gold  crown-cutter,  267. 
Gold  crown,  repair  of,  267. 
Gold  cusps  for  bridges  in  one  continuous 
piece,  323. 


Gold  cusps,  solid,  95,  106,  107,  318. 

Gold  inlay  anchorage  bar,  228. 

Gold  plate  lined  with  platinum,  75,  413. 

crown  metal,  75,  412. 

solder  filings,  76,  126,  415. 

solders,  formulas  for,  414. 

standard  of  carat  and  gage   required, 
75,  412. 

tips    for    natural    crowns,    method    of 
constructing,  155. 
Gold  plates  and  solders,  411. 
Gold,  platinized,  413. 
Gold  seamless  contour  crowns,   118. 
Gold  seamless  cap-crown,  112. 

adjustment  of,  122. 

contouring  of,   118. 
Griswold     attachments      for     removable 

bridge-work,  309. 
Gutta-percha  cement,  165. 

combined    with    oxyphosphate    for    ce- 
mentation, 165,  168,  172. 

in  filling  root-canals,  25. 

in  preparation  of  routs.  38,  '■'>'■>,  141.  144 

use     of,     for     cementing     crown-     and 
bridge-work,  165,  167. 

Heat,  use  of,  as  a  disinfectant,  9,  20. 

Hollingsworth  system  of  crown-  and 
bridge-work,  316. 

Hollow  all-gold  dummies  for  bridges, 
206. 

Hollow  wire  for  posts,  86. 

How  crown,  49. 

How  screws,  m.'. 

Howland-Perry  crown,  48. 

Hub-mold,  108. 

Hygienic  condition  of  the  mouth  as  af- 
fected by  bridge-work,  208. 

Hygienic  consideration  of  collar  crowns, 
81. 

Hygienic  preparation  of  the  mouth  for 
crown-  and  bridge-work,  3. 

Impression  of  crowns  or  roots,  68,  111, 
111',  115,  421,  424. 
for  bridge-work,   189, 197,  219,  243,  287. 
materials  for  taking,  64,  88,  102,  112, 

188,  420. 
trays  for  taking,   112,   419. 
Impression    and    articulation    combined, 

188,  423. 
Inlays,  gold,  153. 

anchorage  for  bridge,  228. 
porcelain,  358. 
Inlaying  of  gold  crowns,  322,  400. 
Insertion  and  cementation  of  crown-  and 

bridge-work,  162,  197,  212. 
Instantaneous  extirpation  of  thepulp,  11. 
knocking  out  of  the  pulp,  11. 


INDEX. 


445 


Instruments  and  appliances,  19,  20,  .">•">. 
63,  65,  7.".,  77,  101,  103,  104,  107, 
114,  119,  123,  166,  167,  168,  214, 
312,  313,  314,  342,  345,  346,  347, 
360,  361,  367,  370.  373,  374,  382. 
383,  390,  419,  430. 
and  materials  used  in  crown-  and 
bridge-work,  93,  194,  428 

Investments   for  soldering,   4L'S. 

Iodoform,  methods  of  using,  24. 

Iridio-platinum  wire  for  posts,  SO,  412. 

Irregularities  of  the  teeth,  methods  of 
crowning   in,    147. 

Isinglass  (mica),  use  of,  in  crown-  and 
bridge-work,  96,  193. 

Kingsley'S  method  of  forming  all-gold 
crowns,  104. 

Kirk's  method  of  cementing  with  amal- 
gam,  173. 

Knapp's  blowpipe,  435. 

Knuckling  a  collar,  methods  of,  102,  118. 

Land's     method     in     partial     porcelain 

crown-work.    .",7'.». 
Lawrence  crown,  47. 
Lead    counter-dies,    method    of    forming, 

113,   117. 
Leverage   in   bridge-work,    ISO,    L81,"   218, 
222,    223,   2117,    232,   243. 
in  extensive  bridge-work,  218. 
Litch's  detachable  bridge,  306. 

partial   cap   and   pin   bridge.    229,    232, 
236,  249,  251. 
Logan  crown,  (»4. 

method   of    mounting,    with    band    and 

cap,  137,  398. 
method  of  fitting,  by  model,  68. 
on  platinum  base.  399. 
Dr.    Baldwin's    method    of    mounting, 
138. 

Mack  crown,  48. 

Mandrels,  use  of,  for  forming  collars,  78. 
Mason  replaceable  fronts,  240. 
Materials  and  processes  used  in   crown- 
and  bridge-work,  409. 
models  and  dies,  424. 
porcelain  teeth,   60,  417. 
soldering,  430. 
measuring  the  size  of  necks  of  crowns 

or  roots  for  collars,  78,  320. 
natural    crowns    or    roots    for    ready- 
made  gold  crowns,  122. 
Melotte's  metal,  424,  426. 

method   of   making  model   and   articu- 
lation   in    constructing   bridge-work, 
190,  426. 
moldine,  425. 
Metal  flange  to  support  crown,  146,  147. 


Metallic  dies   and  counter-dies,  424. 
Metallic  dies  for  forming  caps  with  cusps 

for  crowns.  95,  105,  107,  426. 
Models   for    bridge-work,    1S8,    199,    218, 

243,  405. 
Molar   roots    decayed    apart,    method    of 

crowning,  146. 
Moldine,  425. 
Models  and  dies,  424. 
Mulyneaux's  fusible  metal,  424. 
Morrison's  crown,  47. 
Mouth,  preparation  of,  3. 

Necks  of  teeth,  average  forms  of,  76. 

methods  of  measuring,  78,  320. 
New  Richmond  porcelain  crown,  50. 
Nomenclature  of  crown-work,  r>'_\ 

Objkctjoxs    urged    against    bridge-work, 
179. 
against  collar  crowns,  81. 
against  crowns  without  collars,  71. 
Obtundents,   use  of,   in  alveolar  abscess, 
30. 
use  of,  in  crown-work,  80. 
use  of,  in  extirpation  of  pulp,  11,   12. 
Occluding  surface  to  collar  crowns,  meth 

ods  of  forming,  95,  97,  102. 
Occlusion,    subject    of,    38,    53,    97,    191, 

201,  218,  227. 
Ottolengui    root-reamers   and    facers,    65, 

66. 
Oxyphosphate  cement,   162. 

properties     suitable     for     crown-work, 

162. 
to  cause  to  set  slow,  163. 

Paer'S  crown,  135. 

Parr's   detachable  bridge-work,   308. 

Partial  crown-work,  149,  209. 

porcelain  work,  358. 

porcelain  and  gold,  158. 
Perforation  of  side  of  root,  treatment  of, 

145. 
Pin  to  attach  gold  crown,  60,  171,  172. 
Pivot  teeth,  46. 

Plaster      impression      and      articulation, 
method    of    taking,    188,    197,    199, 
218. 
Plate-bridge,   removable,   287. 
Plates  and  solders,  411. 
Platinum  plate,  411. 

advantages  in   crown-work,   75,  411. 

and  gold,  411. 

solder,  388,  416. 

wire,  411,  412. 
Pliers  for  shaping  collars,  75,  101. 
rolishing  and  finishing  crown-  and  bridge 
work,  161,  196. 


446 


IXDEX. 


Porcelain,  advantages  of,  for  inlay-work, 
359. 
teeth,  use  of,  for  inlay-work,  383. 
comparative  fusing  points  of  different, 

357. 
erosion,  use  of,  for,  378. 
heat  effect  on  color  of,  348,  352. 
ingredients,     chemical      and     physical 

character  of,  338. 
coloring  of,  330,  353. 
gum  enamel,  fusing  of,  330,  354. 
furnaces  for,  344. 

pyrometer,  use  of,  in  fusing,  347,  351. 
inlays,  358. 

merits  of  high-  and  low  fusing,  356. 
shrinkage  of,  in  fusing,  348. 
tips,  379. 
Porcelain  crowns,  ready-made,  61. 
Ash's  tube-teeth  and  crowns,  70. 
Brewster,  69. 
Davis,  69. 
Fellowship,  69. 
Logan,  64. 
method  to  facilitate  the  adaptation  of, 

to  the  root,  64,  67. 
remarks  on  use  of,  71. 
Porcelain  and  gold  crown  without  a  col- 
lar, 120. 
Porcelain  and  platinum  crowns  for  teeth 

with  living  pulps,  100. 
Porcelain  dental  art,   337. 
Porcelain  bridge-work,  403. 
adaptation  of  saddle  for,  405. 
cementation  of,  406. 
criticism  of,  403. 
formation  of  dummies,  404. 
framework   of,  strength   required,    403. 
proper  and  improper  forms  of  construc- 
tion, 403. 
solder  required  for,  405,    106,  416. 
Porcelain    crown    with    gold    collar    at- 
tachment, 83,  137. 
Porcelain  faces  for  bridge-work,  191,  186, 
404,  417. 
for  crowns,  88,   137,  322,  391,  417. 
Porcelain    fronts,    backing    for,    00,    102, 

322. 
Porcelain   inlays,   cavity  preparation   of, 
for,  360,  377,  378,  370,  380,  381,  382. 
cementation  of,  375,  382,  385. 
dies  or  molds  for  shaping  matrix,  366. 
former  and  present  methods,  358. 
furnaces  for  fusing,  344. 
fusing  or  baking  of,  348,  370,  373. 
gassing  of,  344,  385. 
high-    and    low-fusing    body    for,    357, 

370. 
matrix,    application    of    body    to,    for, 
370,  372. 


Porcelain   inlays,   matrix,   investment   of, 
for,  369. 
matrix,  shaping  and  removal  for,  363, 

365,  369,  383. 
method  of  etching  with  a  diamond  to 

attach  cement,  374. 
points  to  bear  in  mind  regarding,  383. 
-rod,  382. 

selection  of  color  of  body   for,   340. 
Porcelain   and  platinum   crowns,  391. 
incisors  and  cuspids,  391. 
bicuspids  and  molars,   302. 
jacket-crown,  393. 
tube  crown,  397. 
Porcelain,  method  of  inlaying  gold  crowns 

with  Jenkins  porcelain,   400. 
Porcelain,    partial    crown-work    or    tips, 

379. 
Porcelain  teeth,  selection  of,  60,  88,  191, 
391,  417. 
some  causes  of  fracturing  in  soldering, 

417. 
veneers  of,  417. 
Porcelain    tips    to    natural    crowns,    158, 

379. 
1  "lists   for    retaining  crowns,    40,   57,   59, 
63,  65,  69,  70,  86,  87,   0.".,    120,    133, 
160,  171,  172,  272. 
method    of    forming,    to    fit    any    sized 
canal,  S7. 
Pouring   fusible   alloy    or   metal,    manner 

of,  424. 
Preparation   of  natural    crowns   or   roots 
fen-  gold  crown-work,  36. 
for  porcelain   crowns   generally,   38. 
Preparation,    special,    of    badly    decayed 

teeth  and  roots,  40. 
Preparatory   treatment  of  the  mouth,  3. 
Principles  involved  in  crown-work,  52. 
Pulp,  capping  of,  8. 

diseases  of,  requiring  extirpation,  8. 
instantaneous    devitalization    with    ex- 
cision of  crown,   11. 
lesions  of,  8. 

preservation   or  devitalization,   5,   S. 
use  of  arsenic  in  devitalization  of,   13.' 
Pulpless   teeth,   their  treatment  and  dis- 
infection, 15. 
Punch  forceps  for  riveting,  for  use  in  re- 
pairing bridge-work,  263. 
Pyorrhea     alveolaris,     bridge-work     and 
cases  of,  234. 
collar  crowns  in  cases  of,  82,  237. 

Ready-made  crowns,  porcelain,  61. 

gold,  121. 
Reaming  of  root-canals,    L6,  65,  86,  132. 
Removable     and      replaceable     porcelain 
fronts,  239. 


IXDEX. 


447 


Removable    or    detachable    bridge-work, 
270,  287. 
l>r.  Alexander's  method,  306. 
I>i\  Bonwlll's,  298. 
Griswold,  the,  309. 
Dr.  Liteh's,  306. 
Dr.  Parr's,  308. 
Dr.  Peeso'B,  295. 
Dr.   Winder's,  304. 

connecting    bars    for,    278,     284,     294, 
331. 
Removable   crowns   and   attachments   for 
bridge-work,  271,  289,  295,  299,  304, 
310. 
Removable  plate-bridges,  -s7. 
Dr.   Bonwlll,  298. 
Dr.  J.  L.  Davenport,  299. 
Griswold,  the,  310. 
Removal  of  crown-  and  bridge  work,  266 
Repair  of  crown-  and  bridge  work,  263. 
Dr.  Bryant's  method,  265. 
Dr.  Shriver's  method,  264. 
Dr.  Starr's  method,  265. 
Dr.  Williamson's  method,   264. 
Repair  of  gold   crowns,  2t'.7. 
Retaining    pin    for    all-gold    crown,    160. 

171,    172. 
Rhein's  method  of  splinting  in  pyorrhea, 

234. 
Richmond    crown,    original    form    of,    in- 
troduced, 46. 
Rod   method   of  porcelain    inlays,   382. 
Root-canals,  preparation  of,  15. 
treatment  and  disinfection  of,   18. 
method  of  filling,  23. 
method  of  treatment,  20. 
Root-canal,   antiseptic   agents   for    treat- 
ment, 21. 
Root-canal  drier,  20. 
Root-reamers    and    facers,     Ottolengui's, 

65,  66. 
Root-trimmers,  35. 

Roots     intervening    between    abutments, 
208,  285. 
special  preparation  of  badly   decayed, 
40. 
Rubber     or     vulcanite     attachment     for 

crown,  72. 
Rules  governing  the  insertion  of  bridge- 
work,   181,   207,  218,  224,   232,   234, 
243. 


Seamless  gold  crowns,  method  of  forming 
from  an  impression,  115,  117. 
process    of    adjustment    and    insertion. 

122. 
ready-made,   121. 
Self-cleansing  Bpaces  In  bridge-work.  191, 

193,  194. 
Sensitive  dentin,  treatment   of,  0,  38. 
Shapes  of  necks  of  tee!  b,  7»i. 
Shaping   teeth    and    toots    for   crowning, 

process    Of,    ■"•  1. 

badly  decayed,  38. 

Shell  anchorage  or  crown.  209,   248,   250. 

seamless,  211. 

how  to  cement.  212. 
Shoulders   on    the   anterior    teeth,   201. 
si..is  for  anchorage  bars,   188,  221.  22s. 

2::  I.  25  1,  295,  328,   l"7 
Solder,  gold,  formulas  tor,  414. 

hard-flowing,  415. 

platinum,  416. 

silver,   415. 

solder  filings,  fluxed,  415. 

soldering,  flux  for,  416. 

investments  for.  428 
Solid  gold  crowns,  204,  205. 
Special  forms  and  methods  in  crown    and 
bridge-work,  !»7.    130,   201,   224.   232, 
234,  295,  304,  316. 

Dr.  Alexander's,  149,   157,  306,  310. 

Dr.  Bonwlll's,  298. 

Dr.    hitch's,   306. 

Dr.  Parr's,  308. 

Dr.  Peeso's,  295, 

Dr.   Spencer's,  305. 

Dr.  Winder's,  304. 
Special    preparation    for    badly    decayed 

teeth  or  roots,  40. 
Spur   support   in   bridge  work.    222. 

anchorage,  223. 
Stamping  press  for  caps,  114. 
Staple  crown.  215. 
Sterilization   of   root-canals,    18,    21. 
Stowell's    porcelain    gold    collar    crowns, 
98. 

spur  anchorage,  223. 
Strengthening  gold  seamless  crowns,  125. 
Sulfuric  acid,  care  in  the  use  of,  31. 

to  open  up  canals.  18. 
Swager,  use  of,  368. 
Syringes,  hot-air,  19. 

abscess,  28. 


Sanger's  diatoric  tooth  dummies,  202. 

method    of    treating    fractured    roots,    Teeth,  porcelain,  60,  417 
141. 
Screws  to  support  crowns,  40,  62. 
Seamless  gold  crowns,  112,  115,  US. 

methods  of  contouring,  118. 


porcelain  veneers,  417. 
Temporary    attachment    of    bridge-work, 

198. 
Temporary  crown,  72. 


448 


INDEX. 


Thickness    of   plates    suitable   in    crown- 
work,  75,  117.  184,  411. 

Tin,  alloys  of,  424. 

Tips,     porcelain     or     gold,     for     natural 
crowns,  155,  156,  379. 

Treatment    of    chronic    alveolar    abscess, 
27. 
preparatory,  of  the  mouth,  3. 

Trimmers,  root,  35. 

Trying  in  bridge-work,  191,  197. 

Van  Woert's  crown,  131. 

■\YARriNG    of    bridge  woik    in    soldering, 
196. 


Weston  crown,   49. 

Wheels  for  shaping  natural   crowns  ana 

roots    for    crown-    and    bridge-work, 

34. 
White's,  Gordon,  method  in  crown-work, 

137. 
Winder's   detachable  bridge-work,   304. 

Dr.  Spencer's  method  in,  305. 
Wire  for  posts  or  pivots,  40,  57,  03,  86, 

133,  160. 

Zinc  oxychlorid,  use  of,  24,  25,  40. 
oxyphosphate,   162,  212. 


COLUMBIA  UNIVERSITY  LIBRARIES  (hsl.stx) 

RK  666  Ev1  1905  C.1 

A  Practical  treatise  on  artifi 


2002449790 


